Is it considered a sin not to financially support adult, unemployed siblings, while continuing to provide for one's mother and her medical expenses, in order to cover the costs of one's children and family?

The maintenance of a poor mother is obligatory upon her affluent son if she has no other child. The maintenance of poor siblings who have no income is also obligatory if the son is their heir. A condition for the obligation of maintenance is the availability of surplus funds beyond the basic needs for one's own sustenance, and that of his wife and children.

The mother takes precedence over siblings in maintenance if the funds are insufficient for everyone. Providing for one's mother and siblings is among the best deeds and a source of blessing in sustenance and lifespan.