mother in laws
Boundaries, ladies, boundaries.
There's a reason these ladies are former mothers-in-law.
First of all, everyone involved is an adult. This makes them peers. No longer is the parent-child dynamic in play... or at least, it shouldn't be. Adults are presumed to be independent, capable of decision-making, and no longer in need of active, hands-on parenting.
As a mother, I cannot imagine that anyone could love my children as much or as unconditionally as I love them.