I don't know where to start. I think it's mostly a vent (is that the right word?...or it's rant?

sorry!!).
There is this guy...a friend I met when I first came to UK with a 3y/o Boxer mix.
He is visiting me 3-4 times a week with his dog to play with my dogs in the farm and do some training with my old-man.
Now he is moving to London and he is leaving his dog because he says there is no space for a dog there. Well I'm really angry with him cause he asked me to take his dog and he said this like nothing is going on!
There has been 1,5 weeks since then. At first I told him I can't cause I'm full! I tried to convince him that he can take the dog with him...but I didn't change his mind! He is moving this Friday and the dog will go to a shelter (I hope).
Now my question. Although I have already many dogs another one won't be a real problem (but I don't want another dog right now) and maybe I can find a good home for him. Am I too sensitive?? Should I let him do what he thinks best?...I really don't know. I feel bad I wasn't able to convince him keep the dog. I feel I'm a looser.