If it is mainly financial support for mother and sister, I would move closer, even if it negates most of your savings. The commute is a killer, so get a teeny tiny place, or room share, and go home on the weekends.
The future growth opportunities alone will make it worthwhile, even if financially it is a bit of a wash for now. You will need to be able to put in extra energy to make those opportunities happen, and the commute is an energy sucker. Try to imagine the best possible life for yourself, with healthy habits, energy, time for you, time for family, all rolled together.