Unless it was summer break, "Joey" couldn't care for his grandmother during the day while his mother was out. After school hours would be filled with homework, sports and all the things that kids are supposed to be involved in. I wouldn't feel right about giving the responsibility of medications, handling and injecting a needle filled with insulin to a child. Transferring a person can be tricky. What if "Joey's" grandmother fell and broke her hip during the transfer? If she choked on food while he was feeding her? If she had a heart attack and died in front of him, with no one else around? Why put that responsibility on a child? I sure wouldn't.
I was fortunate to have my sister to help in caring for our father, in his home. That is where he wanted to live and die. It was one of the hardest yet rewarding things I've done in my life. Our siblings helped out a few times in the beginning then walked away. I don't know what I would have done without my sister. To those (and I know there are many ) caring for a loved one on your own, I admire and applauded you!

My husband and my seven year old were the only two members of my husband's family who pitched in when caring for my late mother in law. The rest of her sons
seldom visited and never offered us assistance, even when my husband was in the hospital then at home recovering from surgery for a month.

Oops I meant Joey's Mom not Karen.?

Karen probably has several siblings who do squat for their Mom and let their underage nephew pull the weight for them!

other family members, what's that?

Other Family Members? Seriously? What world do you live in? We are, for the most part, ONE child, with the entire load! Physically and Financially!