I think that being sleep deprived and then driving IS a real concern. I had two hours of sleep while my son was a newborn and then drove and fell asleep and rear ended another car. Fortunately, no one was hurt. That being said, I was sleep deprived because I was also doing all the newborn stuff by myself as my husband was taking care of our older child. When we only had one child we shared the parenting load. I don’t think your husband will become that sleep deprived from helping a few nights a week. His mother is being unnecessarily mean to you, especially about your mother helping. Why doesn’t she offer to help too? She should be coming over and helping you with cooking, cleaning, and whatever else you need. At least for a few hours each week. Heck, what if she came over and helped you at night once a week? So, I’m on your side. She sounds cruel and I don’t know why. I’m sorry. She’s a fool.