My anatolian shepherd is becoming aggressive to my family. Please help

Im going to try to make this as short as possible, but I know its insanely long so sorry... My parents got 2 dogs 2 years ago, one which was an anatolian shepherd. They intended for him to be a guard dog, but all they did was stick him outside on a tie out. So he never got socialized to livestock or to people except for my family. I was away at college during this time so I didnt know what was really happening. Then I moved back in when the dogs were about 1 year old and Ive been training them since. Now they are amazing. They are perfectly behaved at home and even though the ASD is still is aggressive towards strangers on our property, if I am there to guide him he calms down and behaves. Pretty much, I became the leader and the dogs know they aren't allowed to mess around with me or with anyone if I am there. Both dogs live outdoors on tie outs, since my dad refuses to let them inside, but I try to make up for it by spending a few hours every evening exercising them, playing with them, and training them. I have been able to train both dogs to behave well around our chickens too.
Anyways, I intended to save up money then move out to a large rural property in a few years and take both dogs with me and have the LGD live out the rest of his life as a real working dog. However, I've run into some issues.
Neither dog is fixed yet, as I was waiting for them to finish growing first before doing that. Since they are both 2 years old now, I feel like now is a good time to do that. But my female dog went into heat a few day ago and I guess finally being grown up and sexually mature, my LGD started to become super aggressive these past few days. He has never reacted like this before during her previous heat cycles, but like I said, i think the fact that he is finally an adult capable of reproduction has caught up with him. These past few days he has started growling, barking, and lunging at my family members whenever they walk by him. Since he is on a tie out, he cant get to them though so nobody has been hurt. Whenever I walk up to him though he stops barking and sits down and behaves. But as soon as I walk away he starts barking again. I wasn't sure if it was aggression or not but when I look from the side, it is definitely unhappy frustration when he barks at my dad and brother. So I decided to keep him in a crate in the shed for now so that he stays a bit calmer. But when my dad and brother went into the shed to get some stuff today, he started barking and growling at them very loudly. I could hear it through the window in the house so I went outside to check what was happening and as soon as I came into the shed he stopped barking and started behaving again.
Anyways, I thought this was just an issue of him being intact still and reacting to my female dog in heat, so I scheduled an appointment to get him neutered tomorrow. But then my dad told me that he has been aggressive to him a few times already these past few months. He has also been aggressive towards my sister too (she lived here for a few months when he was a puppy, but then she moved out for a year, and then came back. He was aggressive at first but then recognized her and got all excited, but then has been trying to attack her at random moments that she passes him. I didnt think much of it at the time because I thought he was just having a hard time remembering her and would stop once he realized she was living here again). Now with his crazy behavior right now, my dad is insisting that we get rid of him. I absolutely do not want to do that, but I do understand where my dad is coming from.
The problem is that my dog is perfectly behaved while I am there, but if I am not there, he is becoming unpredictable, and once again, my dad refuses to let him indoors where I can watch him, so he is unsupervised often. My family is not dog-savvy (it was a mistake for them for get him in the first place) and they dont know how to be leaders to dogs. Ive tried to teach them how, but I dont know how to teach someone to change their body lanuage into something a dog respects. I love this dog with all my heart, and I have complete control over him and feel confident and safe handling him, but once again, only when I am there does he behave well. I am hoping that neuetering fixes the problems he is having, but I am not counting on it since he is an LGD breed. My parents are telling me that we have to get rid of him, but I want to make it work somehow and I am most likely going to change my plans and move out within a few months instead so that I can get him out of their life without actually rehoming him. I don't trust him if I were to rehome him honestly. Because of the way my parents raised him, he is aggressive to new people and also not socialized to livestock to be a proper working dog. In addition to that, he also has environmental allergies and hip dysplasia. I dont want to rehome him to a city home because I dont believe that is good for an LGD (plus he would hate all the strangers and dogs everywhere), but nobody on a farm will want a dog like him either that is untrained as a working dog, that also has health problems. So like I said, Im just going to move out asap instead and take him with me. However, in the meantime until I find a house and sort that all out, I still need to make sure he doesn't hurt my family when I'm not around. How in the world do I do this? I dont really understand why he is suddenly becoming aggressive towards his own family that raised him. Yes, rehoming him seems like the logical answer, but I truly doubt he will be safe around a new owner (unless they are a super experienced dog trainer/behaviorist that is used to dangerous dogs) and I really fear that he would hurt someone if he were rehomed and would have to be euthanized for aggression. And I know all this makes him sound like a horrible dog, but I know he, and everyone around us, is safe as long as I am there to guide him. I dont know how to say this without sounding like a narcisist. I am very animal-savvy and very good with animals. Ever since I was 8 years old, I was working with different types of animals, both training them and rehabilitating them. I can read animals way better than I can read humans. When I moved in with my parents and took responsibility of the dogs, I started taking dog training courses and learning everything I could. I was able to take my dogs from psycho hyper teenagers into well behaved, calm, and happy dogs. Thats why I am saying that I feel like my LGD will live his best life if he stays with me, but I really need some serious help with his aggressive behavior to my family when I'm not there. This is also important in case I ever need to travel and need my family to watch him for a few days. I cant have him attacking anyone while I am gone. I will try to move out within the next 3 months so that my parents dont get rid of him behind my back or shoot him (like my dad has threatened), but like I said, in the meantime it's critical for him to stop his random aggressive outbursts when I am not there. Please, does anyone have any advice here? Getting rid of him is obviously the easy solution, but I don't believe in giving up on my pets when there is a way around it. Plus, he is amazing with me. He respects me, doesnt challenge me, listens to me, and is bonded to me. I dont think he deserves to be euthanized or rehomed because he can have a perfectly happy life with me in a different house. But it's also not realistic for me to be watching him 24/7.