Is it obligatory to give money to a father who registered his property in the name of his second wife, raises weapons, curses his children, and demands money, and is it obligatory to visit him despite his actions?

What the father did by writing his money over to the second wife to deprive his children of it is forbidden and impermissible. It does not count as her possession unless she takes hold of and seizes it. Similarly, his cursing, reviling, and threatening with a weapon are forbidden, as evidenced by the Prophet's (peace be upon him) saying: "Abusing a Muslim is a Fusuq (disobedience)," and "Whoever points an iron weapon at his brother, the angels curse him." His demand for his children's money to deposit it into his wife's account is impermissible. His children are allowed to prevent him from doing so, and this does not constitute disobedience. It is permissible to refrain from visiting him to ward off his harm and injury, and to suffice with inquiring about him by phone.