Am I obliged to financially support my father who is capable of earning an income for himself, given my difficult financial circumstances and increasing obligations?

If a father owns real estate that he can sell or rent out, then his children are not obligated to spend on him. This is because financial support for a relative is only obligatory if the relative is poor, possessing neither wealth nor income.

However, if the children can spend on him without hardship, then this is an act of ihsan (benevolence) and a righteous deed for which they will be rewarded.