What is the ruling on a man marrying his divorced wife and taking her back into his custody, knowing that his mother vehemently refuses this and threatens him with her displeasure until the Day of Judgment?

Life is a realm of trial and tribulation, and affliction befalls a believer to elevate their status and expiate their sins. The questioner's mother exerted tremendous effort in raising him, and his duty towards her is righteousness, kindness, and striving to please her. His mother's stance regarding his ex-wife has its justifications. Orphanhood might be easier than living in a tense environment, for the Prophet, peace and blessings be upon him, was an orphan, and that did not harm him. Obedience to parents takes precedence over obedience to others, and their رضا (pleasure/contentment) takes precedence over the pleasure of people. What his ex-wife did to the questioner and his mother is a sufficient excuse for the mother's stance. Losing his mother is a definite loss, unlike the potential return of his ex-wife. The questioner must obey his mother. If his wife shows maturity, he should try to convince his mother; otherwise, he should marry another. And he should supplicate to Allah to choose the best path for him.