Sounds like you've already ruled out the daycare idea, but I'll toss in my experience just in case!
We went that route. BIG mistake. You know all the wear, tear, & damage ONE kid can do? Multiply it..
Picture this - she's busy dealing with one kid while five more are bouncing off walls in the next room. She's too tired to clean up after thay leave, so you do it after YOUR workday. And I don't mean normal housework, (that
should be shared duty), I mean a daily heavy-duty mess.
Furniture wears out fast, as do carpeting & paintwork. And don't expect parents to pay when their little Johnny destroys something!
It led to a lot of stress between us, and it impacts the kids badly too. Their things become everyones, their Mom is spending a lot of time with other kids, etc....
Financially it's short-term profit, long-term loser.
In every other way, all-time loser.