Why cant my child have a new heart?

My little boy has down syndrome and a terminal heart defect. I have been told he is not a good candidate for a new heart. However giving him a heart is just as risky as any other child. is a child's right to live based on future abilities to pay taxes give to society does he need to be beautiful and smart. who is to say he wont be any of these things. why does he have less rights. its painful to know that the medical world do not want to do all they can for my baby boy. My love for my son is as deep and as strong as any other mother.