@Beau
Actually I'd say from the OPs posts it sounds as if they baby is sleeping well in the dark room in the day. The 'issue' with that is simply that the OP doesn't like it (and that the suggestion came from her DILs mother). I'm probably wrong but I'm getting the feeling that she hasn't been able to babysit and is blaming it on the baby needing to sleep in a dark room which she doesn't have sorted at her own home. It works for the OPs DIL (& son! He's part of the decision making to, the Op can't just blame her DIL and her mom) so therefore it's not a problem.
The OPs first post was regarding the scratching and swaddling. Later posts have suggested it may be sleeping/gro bags which most parents these days use. Also not a problem (and indeeed as pointed out by a pp, much safer). Funny how the OP hasn't come back since that was pointed out to her.
I don't think there's any 'problem' here other than her not liking how her grandchild is being raised. Hopefully the OP can see now that plenty of other grandparents have felt like this, but realise that they need to allow their children and children-in-law to parent, rather than trying to control how they parent.
OP, if you want a good relationship with your grandchild, you need a good relationship with his mother. Don't ruin it just because she's doing things differently than you would.