Career Path Change From Attorney to Running Family Restaurant

I (28 M) am currently an attorney in a state in which is transferrable as it is a Uniform Bar Exam state. I have been licensed for about a year and am at a firm that has a good reputation doing PI work. I do not necessary love the work but I am full-time remote and the stress-level is pretty low. I have been with my girlfriend for about 7 years and we have been living together for the better part of 4+ years now.

As of late (say 5 months), my mother has been trying to get me to move back to my home state (over 8 hour drive away) and run the family restaurant. I originally went to law school because my brother was going to be taking it over but he unfortunately passed when school was commencing. I have a sister too. However, she is not physically or mentally capable of running the business. The family business has been around since the 1960's and there is currently just one left -- the one my mother runs. My mother is now age 65 and I know she is wanting to retire but quibbles over the fact of doing such because she knows that if she goes, so does the restaurant and the sentimental love she leaves behind.

My girlfriend has told me she will not relocate and refuses to move back to my home state. The restaurant does well for a single-restaurant. Revenue in the 5-6 million range. I too am distraught and feel like I am at a mental crossroads of being at the beginning of my career as a lawyer and having the career change to running the family business to ease the stress of my mother and run the business.

I do not know what to do. I have no friends where I am but am involved with her family and it is close. Moving back would bring me closer to my loved ones and friends but with the cost of losing my girlfriend and committing to a career change at such a young part of the journey. Any advise would be helpful and am happy to answer questions. Thank you all, I really appreciate it!