Congratulations on the birth OP, and I'm sorry you're having such a tough time.
My DM would be exaclty the same as yours.
But, I'm trying to think of it from Grannie's POV.
Hope I'm more generous with my time when I'm a GM, but to be honest, having had my youngest at 35, I know that my the time my eldest is a mum, DH & I won't have had any quality time for us for decades, and will still have 3 DCs at home.
It was a life style choice we made. I made choices and sacrifices to be a SAHM, which have greatly affected my earning potential & will have life long implications for my pension. I can see my DD, thinking I'm a mother earth type, who loves being at home being surrounded by DCS, will think this will role out to include her own DCs, but I don't think it will.
I'll probably be of the "sorry, it's my time now" school of thought, and it'll proabably go down like a lead balloon.
I think I'd be wanting my DD's OH to step up after two nights - at least sticking to visiting hours, and dropping DS/DD off on his way to the hospital in the afternoon, picking him up to sleep at his house.
I would help out, but 60 is quite an age to be looking after a 1 year old for any legth of time. xx