What is the ruling of Islamic law concerning a young man who spent his savings on marrying off his sisters and now wishes to marry but is hesitant between looking after himself or continuing to help his sisters?

It is obligatory to maintain ties of kinship with sisters, and it is not permissible to abandon their care with kindness, while seeking reward for that. It is preferable to combine assisting them with marriage and providing what you need for your own marriage. If that is not possible, prioritize your own marriage, for the Prophet, peace and blessings be upon him, said: "Start with yourself." The trousseau of a woman is not an obligation upon her or her guardian; rather, it is an obligation upon the husband.