Never, ever, ignore official mail.
He could have responded in crayon and the court would have ordered paternity testing and he would be off the hook.
Making the biologic father pay for their children is not wrong. Getting the mother to name the father in order to get them off tax payer money is the moral and ethical thing to do.
Ignoring a court letter naming you a father is a bad mistake. These things happen, I was named in a paternity suit when I was 19 by a total stranger. All I had to do was deny it, it didn’t even procede to blood testing.
This Family Court false paternity scandal is a common problem, as evidenced by the 2 of the fine posters on this tiny thread have been through this horror!