Is a person considered a sinner if he cuts off his brother who is wasting his money, while his family in the homeland needs financial help?

The questioner is not religiously obligated to spend on his brother unless the brother is poor and in need. If the brother's income is sufficient for him, then the questioner is not obligated to give him money. Relatives in need are more deserving of assistance. It is not permissible to abandon or shun him; rather, it is obligatory to maintain ties with him and visit him. He should be advised against extravagance and reminded of the Prophet's (peace and blessings be upon him) saying: "The feet of a servant will not move on the Day of Judgment until he is questioned about his life and how he spent it, about his knowledge and how he acted upon it, about his wealth from where he acquired it and in what he spent it, and about his body in what he wore it out."