My guess would be he pulled that complete antler out his skull last year in the rut. I have seen bucks do that and grow just a spike like that. It is not genetic like others have said. He has one good antler side with a typical 5 showing. If it were me I would not be worried about him since he is passing on 10 point genetics. Bad thing is if he is a fighter he will break the spike side off again.
The other buck is a toad. He looks to be 5 in those pics but could be 4 with better daytime pics.