I'm apologetic for your child.
I feel sorry for your child. I understand how challenging such a situation can be. I kindly request, receive my heartfelt condolences.
I feel regretful about the little one. I know what challenging such a situation can be. I kindly request, accept my genuine apologies. I genuinely am saddened for the inconvenience brought about. I'm hoping that the little one will forgive me.