Phil Carey was off the scene for months because of a bout with cancer. They worked it into the storyline around New Year's Eve by having Asa be stricken with a near fatal heart attack after Spencer burst into his penthouse and handed him a picture of Emma Bradley. Emma is Spencer's mother which is why they're leaning towards the idea that Spencer is Asa's illegitimate child. Anyway. Asa was hospitalized for months and just came home which is why he's in the wheelchair. I don't think Phil is really wheelchair bound. I think it's just the Asa character.