Ex mother inlaw

My ex mother inlaw miscarried years ago and would like me to give my child her babies middle name because they share the same due date. Not to mention my son was born on the date she had her miscarriage. I don't think I can do that. And I already had a name picked out if it's a girl. I've had it picked out for years. Her son an I have had such a nasty break up. I just don't feel like giving his family that option is fair. I'm 3 months pregnant. Her son is not involved with this pregnancy. Not once has she asked if I was ok. Or if I wanted company to any appointments. Yesterday was the first time she asked me anything and all she asked was for the due date and could I give her the middle name. Not if I was feeling ok or if the baby was ok so far. Just due date