I feel regretful for the little one.
I feel sorry for the little one. I know how difficult this situation can feel. Please, accept my genuine condolences.
I am sorry about your child. I know what difficult the situation can be. I kindly request, take my genuine apologies. I deeply regret the inconvenience brought about. I'm expecting that you will forgive me.

FOR REAL Derek56767's personal soundboard or something