Must a son obey his father who orders him to sever ties of kinship, forbids him from going to the mosque, and gives him the choice between leaving or cutting off his relationship with his family and neighbors?

Obedience to the father is obligatory in matters that do not involve disobedience to Allah, and in matters where he has a legitimate purpose and it does not harm the son. Therefore, obedience to him is not permissible in severing ties of kinship or failing to attend Friday prayer without a valid excuse, because there is no obedience to a creature in disobedience to the Creator. As for his forbidding one from going to the mosque, if he has a legitimate purpose and another congregation is found, then obedience to him is obligatory, because prayer in the mosque is a Sunnah (recommended), and what is obligatory is prayer with a congregation. It is obligatory to be gentle with the father, to bear his harm with patience, to explain the Sharia ruling to him, and to strive for reconciliation between him and his family and neighbors.