I am 51 years old and had my liver resectioned on November 30th last year. My tumor was about 10 cm and they took half of my liver, but it does grow back in an amazingly short amount of time - like in one month. I spent 8 days in the hospital. Once home, I tried to deal with my pain as much as possible with Ibuprofen, at least during the day, and take the heavier pain meds at night which caused serious constipation. I took stool softeners and ate a lot of prunes! (My sister wouldn't let me go to bed one night until I downed 10 of them.)
It took about 2 months for me to get back to normal. For the first month, I felt like I'd been hit by a freight train. I ventured out a few times to a few functions. (The Woman's Club named me Woman of the Year so I made it to the December meeting, but it took a lot of effort.)
I had a lot of pain on the right side where my surgery was and when I went for my three week check up, I had fluid which had built up on that side which I believe they call ascites. Once I had that drained, my pain was much reduced. Before it was hard to get comfortable enough to sleep.
I still have some pain from the inner incision when I sneeze or laugh. Like Evan said, your life doesn't ever really get back to normal, but your mother might have a good chance.
Unfortunately, they found cancer in one of the lymph nodes they sampled durning surgery, and they told me I had a 70% chance of recurrence which it has done. The new tumors are growing really fast in my liver. I may start chemo next week. I had been on a clinical trial for sorafenib (Nexofar), but it didn't work for me.
Good luck with everything. I think if you're with your mother for one month, by then she'll be able to do most everything by herself. In that second month of recovery, I'd have a day where I felt suddenly so much better.