Can a 3rd party sue for medical malpractice on behalf of someone else without power of attorney or health prox?

Parent A is in the hospital. Child A has health care proxy %26amp; power of attorney (in addition to being the executor of the will). Child B wants to sue the hospital for malpractice (possible case, though not airtight). Child A doesn't want to sue at all. Does Child B have any right to sue on behalf of Parent A (still living at this point)?Can a 3rd party sue for medical malpractice on behalf of someone else without power of attorney or health prox?A child cannot sue, so no. And even if they were adults, they couldn't sue either.