Many neonates are not self-sustainable after birth. Some will never become self-sustainable and will depend on machines and medications to survive for the rest of their life.

Most elderly people including yourself some years from now will not be "self-sustainable". You will need help to move around, you will need medications to survive and all sorts of help.

There is a congenital disorder which makes you insensitive to pain. Does that make you not human?

It is a rather dumb argument.