"Is it true that after 1 year of no contact it could be considered child abandonment?"
*** No. As long as he is not the "parent, guardian or other person charged with the care or custody", he cannot be charged with abandonment.
Missouri Code:
"Abandonment of child in the first degree, penalty.
568.030. 1. A person commits the crime of abandonment of a child in the first degree if, as a parent, guardian or other person legally charged with the care or custody of a child less than four years old, he leaves the child in any place with purpose wholly to abandon it, under circumstances which are likely to result in serious physical injury or death.
2. Abandonment of a child in the first degree is a class B felony. "
and
"Abandonment of a child, second degree--penalty.
568.032. 1. A person commits the crime of abandonment of a child in the second degree if, as a parent, guardian or other person legally charged with the care or custody of a child less than eight years old, he leaves the child in any place with purpose wholly to abandon it, under circumstances which are likely to result in serious physical injury or death.
2. Abandonment of a child in the second degree is a class D felony. "
Accept the fact that he IS the childs OTHER biological parent and has ALL the rights entitled to him by the court..... whether he pays child support or not. And whether he sees the child (or pays the support) or not, his biological rights as a father don't just 'terminate'.