I am a single father and I too am getting some help from family for pre-med. During med school I could hire some kind of nanny or something (which might not be that bad), but I would much rather have somebody close to my daughter spending time with her while I am not there that is why I am going to have my sister live with us and sort of play "house wife" and help me out while she too is going to undergrad school (my daughter will be in school during the day). She gets to go to school without working, and I get the help I need with my daughter. It helps out both of us and of course my daughter. Hopefully I will be home on most nights, but it will be nice to have the freedom to be a little flexible between school and home.
I might suggest you try a similar approach. See if there is a close family member or friend that is stuck in the whole "working paycheck to paycheck without time to go to school" loop. Maybe he/she will be willing to help you out around the house and with your daughter/son in exchange for free rent and the ability to go to school.
I guess another option is to hire a nanny. I dont have much experience with this though.
It seems hard, but I know a lot of single parents go to med school so I know its possible.