And there are full-grown adults with similar disabilities and their caregivers are able to take care of them.
No. there are people paid to care for them, who do it, sometimes in a slipshod mannner.
Yes there are full-grown adults with similar disabilities cared for by loved ones. They may get a nurse to assist them, especially for nights. But there are people who do it. As for "slipshod", it happens in the institutions as well.
-A8