So my sister is a single mother (no father in the picture). She's starting some course once per week and has proposed to my 17 year old son to babysit my nephew (5) from 6 pm to 10 pm, which involves putting him to sleep. She offered to pay him. She's a really difficult person, I even suspect narcissism or mental health issues. We are not on speaking terms right now (after insulting me and lashing out at me for I don't even know what exactly) and she obviously didn't discuss this with me.
My son has no experience babysitting, let alone putting a child to sleep. He already works on weekends in a grocery store. He has a class early morning the next day and he's one of these people who needs to sleep more than 8 hours and who dislikes to wake up early. He oftens tells me that he's tired.
Normally, my 76 year old mom was babysitting my nephew, but she has arthritis and has trouble walking. So my son is the replacement. Also, my son stays at my mom's (15-20 min away) because she lives closer to the college than us (another town), so he won't be going to sleep before 11 pm or later. She might offer that he sleeps in her flat, but she has cats and he's allergic.
When my mom was taking care of my nephew, my sister lashed out at her several times if my mom didn't do things the way my sister wanted (for example, gave him food before sleeping instead of recognizing that asking for food was just an excuse to delay sleeping) and my mom was really upset with her several times. I don't know if my sister will dare getting upset with my son who has no idea about childrearing. I'm also worried that she'll rely on my son way too much (like to babysit her son for some outings too) and ask for more and my son will feel bad saying no.
I just don't think that being involved with her is a good idea. She can hire a babysitter, but I guess she's counting on my son feeling bad to ever saying no or bailing out like babisitters do. Or maybe it's a power play to show me that even if I don't talk to her, she will still have a relationship with my son? I don't know. AIBU?