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
A8 -- getting a home-care nurse takes a whole heckuva lot of money. I went through that with family members. Insurance craps out quickly on that. It's unrealistic for many families to say "get a nurse."
God bless you for your choices in your situation, but that can't help but impact your opinion of families that make a different decision about the best way to care for their child. I would ask you to have some compassion for them and their choices as well.