How old was the oldest child? It’s not unheard of to have a 10 or 11 year old watching over their younger siblings, but I don’t know the details of this case.
that was a long time ago. I don’t think the average 11 year old could deal with an infant ( nor should they have to- it’s their mothers child, not theirs.)
Find one/all of the kids dads and see if he’d take his crotchfruit for awhile.