What is the ruling regarding a wife returning to her husband, who does not pray, after a two-year divorce, and is the guardian's consent required for her return, and who would be her guardian in this case, her son or her father?

There is no good in returning to a husband who has completely abandoned prayer. It is possible to stipulate his repentance and his commitment to prayer for marriage again, with a new contract, the guardian's consent, and two witnesses. If this divorce is the first or second, a new contract is required. However, if it is the third, marriage is not permissible unless you marry another man first.