My mom hasn't had a flight outside of the US since she started availing of wheelchair service, so I can't vouch for "all the way" in the case of the OP, but I can say that the extent of the service has really impressed me (i.e it really has been curb to curb).

Since she doesn't normally use a wheelchair, she initially felt kind of embarrassed by resorting to special assistance, but the benefits of being looked after far outweigh the downsides of her possibly falling down in airports or simply needing to take rest breaks during long walks. In any event, the embarrassment phase is now well behind her, and she is grateful that the program exists.

The special assistance request forms do ask for specifics about the extent of your immobility (using carefully crafted language that is simultaneously sensitive and on point), by the way.