Regarding your anger, you have every right to be enraged with your siblings since they seem to be shirking their responsibilities. But don’t have any guilty feelings, for feelings of this nature are unwarranted. On the contrary, feel good about everything that you are doing for your father. Psychologically, guilt is often an inner anger that one feels toward another.
Once you accept that you have justifiable anger you may start feeling less guilty, enabling you to stop wasting your energy on a painful and unproductive emotion. May Hashem give you much berachah and nachas for all the chesed you are doing. Hatzlachah!