Is it permissible for a young man who has no income and relies on the support of his poor parents to give a small amount from his personal allowance in charity to someone in need, and is it permissible for him to intend by this act to benefit his deceased father?

It is permissible to give a small amount from one's personal allowance as charity, and one will be greatly rewarded for it, for deeds are distinguished by the strength of their motivation and the sincerity of their intention, not by their quantity. It is also permissible to give this small amount in charity on behalf of a deceased father, and he will receive its reward; this is a matter of consensus among scholars. The intention must be solely for Allah, yet the reward of the charity can be dedicated to the deceased father, for even a small amount will benefit him and its reward will reach him.