The only thing I would caution is that mobility service is not a paid companion service. Air Canada is pretty good at this in my direct experience (~2 years ago I broke my foot, and then did YOW-YYZ-SFO return and then YOW-YVR-SYD return with it) but this forum is littered with CBC articles where someone's parent got left somewhere and not picked up, because mistakes can be made and IRROPS situations can throw things in to chaos. There are hand-offs going Dom - Intl / Transborder for example, and sometimes your dad might have to wait for someone at those points. Just make sure he's still paying attention to where is is going and what he is doing and if he needs something he speaks up and asks for it.