I am sorry for your child.
I'm regretful for your child. I know what difficult such a situation can feel. Please, receive my sincere regrets.
I'm apologetic about your child. I understand what difficult the situation might seem. I kindly request, receive my heartfelt condolences. I genuinely feel remorseful for the trouble brought about. I'm hoping that your child will pardon me.
Avengers Infinity War