I"m kinda looking for advice and kinda venting.
I don't blame you a bit for being stressed out! I hope your DH is doing better after being at the ER.
I think a 1 1/2 yo would want a tight bond with someone and who better than his grandmother and/or grandfather that he lives with, who he sees more than he sees his own mother. I'm surprised that his mother would call the other grandmother to watch him since I would hope that by the time she is home from work most days, the baby is sound asleep. If she has a b/f, she doesn't spend the night with him on occasion anyhow?
I hope she can get her act together and you get your DGS back! Let us know how it's going!