Disabled people have a lot of needs and often live in poverty if they don't have family to support them. On their own, they often can't afford a car or gas to put in it, but have more than average number of doctor appointments to get to. I know people (in the US) who receive a mere $700 per month in disability income, and yet have monthly medical expenses out of pocket (after medicaid) of $600. That leaves $100 for their rent, utilities, food, transportation, clothing, etc. There are other services that can fill in the gaps for some of those things, but disabled people tend to have less energy and resources than most to go after them. They have huge needs and not everyone has family able to assist them. Also, I've seen several cases where one person's disability financially wrecks the whole family.
But the real issue is what does your friend think about all this. Has your friend complained to you about this? If he's not complaining, perhaps he's seeing a need he is more than happy to fill. The speaks of generosity and love. He's the one who gets to decide if he makes it his "problem" or not. And I put "problem" in quotes, because to him, maybe it's not a problem at all. And in any case, you don't really have a say in it all.