My son has 3 children age 1 ,3, and 11.never married to mother.she gave them to him.they have notorized paper basic laws for visiting between themselves. She has left state no contact now for a week.This is her time for having them and for summer. We have dna. Does he have to let her have them now? And she has been violent, no job.

The notarized paper is practically worthless. He needs to go to court to establish custody, support and visitation. He should get an attorney and file as soon as possible.

Abandonment doesn't enter into this, especially at this time.

Agreed, if you actually paid a notary you threw money away,
First neither parent can just give their rights away, and the only legal custody agreement is one done in court.

So are they married ?

If not married, or even if they are, is he on the birth certificates of all of the kids?

You said you have DNA ? The mothers to find her ? Or a DNA test done by the court proving paternity.

Again if the tests were not done though the court, they have really no value either.

State done DNA.dad is on birth certificates. Notarized letter was an agreement between themselves. Never married. Can she take them out of state? DNA was done to prove paternaty.

Like I said the agreement is practically worthless. Without a court ordered visitation schedule, she would be free to move. Again, your son needs to go to court IMMEDIATELY!