Deprivation of paternity

Good evening. Please tell me, there is a child from a legal marriage (a 13-year-old boy), they divorced a long time ago, at that time the child was a little over a year old. He currently has a second family, children. It is located abroad, has a group, although it was bought. He does not take part in the upbringing and development of the child, he is not interested. The only thing is that alimony is deducted from his pension. Previously, when he worked officially at work, alimony was collected, later, thanks to various frauds, he refrained from paying alimony. She has two children with her second husband. The older child calls him dad, although he knows the truth. The man has a UBD certificate. Therefore, children are entitled to various benefits, including for education in this category. A man wants to establish paternity for an older child, and not only because he considers his child or because the child calls him his father, but also so that the older child can enjoy the same benefits that belong to children of UBD. Is it possible to do something about it, for the sake of the child?