The weight of a bike or a wheelchair matters a lot less when you're at low speeds on level terrain without many turns, which describes a hospital to a T - they have to be able to get gurneys through these spaces, and if you think a wheelchair is heavy then brother have I got news for you.
But the moment you go outside now you're dealing with ramps and hills.
I'm 38, more fit than most, I had to interact with my father-in-law's wheelchair this weekend for the first time. He is 73 and expected to travel with it everywhere, lifting it in and out of some kind of a vehicle. I would _very_ much describe it as heavy, especially in the context of a 70+ (maybe 60+, maybe 50+) year old individual. I'm wondering what the news is.
But the moment you go outside now you're dealing with ramps and hills.