weak hind legs

Good evening everyone. I am currently crying the Niagara falls as I am having a horrible decision to make, allowing my 4 years old baby bunny to go to binky heaven or not. He had E. Cuniculi from birth which I tried treating, had several GI stasis to cure but recently, he has lost some weight...

My 10 year old Dutch Dwarf, Vince, has congestion in his lungs and is on antibiotics. He's also experiencing weakness in his hind legs. He can still get around but doesn't run around like he used to. It seems like getting up from a laying position is most difficult but once he's up, he walks...