Is the son obligated to move with his mother to another city, even if this causes the mother to separate from the father who does not pray, knowing that the son is studying a major not available in that city?

The permissibility of a wife remaining with her husband who abandons prayer is based on the difference of opinion regarding the ruling on one who abandons prayer. Whoever does not consider him a disbeliever permits her to remain, and this is the view of the majority of jurists. The wife must advise her husband, instill the fear of Allah in him, and explain the gravity of abandoning prayer. She must remain where her husband resides unless he permits her to move.