Is the father obligated to provide for his two unmarried sisters, taking into account his financial and health situation, and the income of the unmarried sisters?

The father is not obligated to financially support his sister if she is financially capable. He may, however, give her charity as he wishes. As for a poor sister, jurists have differed regarding the obligation of maintenance for a needy relative who is an heir. The preponderant opinion is that the father is obligated to provide for his poor sister, even if there is someone who prevents her from inheriting. The obligation of maintenance includes every well-off relative, male or female, towards those in need. However, the maintenance of one's wife and children takes precedence over the maintenance of other relatives.