NTJ. Don’t worry about Trevor if he hasn’t ever stepped up and helped you out with his brothers. He can do the same as you did when he hits 18. That’s only 4 years compared to your 12 years of parenting. Your mom is TJ and younger brother kind of a jerk due to what he said to you!
NTJ, tell all those family members to buy the baby clothes and there would be no problem. Your sister is a major jerk, I’d put her in a time out and maintain low/no contact. No one has the right to tell you how to grieve your daughter.