Well Mark, it's kinda hard to answer questions about your mother without really knowing what her specific issues are, but reading the forums IS the best idea to start with. Not every plan works for everyone; something personal for her is best. The same goes for exercise.
For me, the best plan is one that I can stick to, and the best exercises are the ones I can do.

I still eat what I love and I do activities that I don't mind. That is the only way to do something long-term, IMHO. I am on a portion-based calorie plan, which I find to be the most flexible.
I do avoid trigger foods: that is, ones that I really have a trouble binging on, but I still eat lots of others in small portions which makes up for that. I made all our favorite dishes more healthy so we still can enjoy them. We do eat out on occasion, picking the most healthy thing we can find but it must fit within my daily calorie limits for the day too.
I have had to work on my emotional-stress eating -- developing personal strategies based on my faith and some other ideas; and this has helped me immensely in my "back-to-good-health" journey. I hope you find some good ideas here to help your mother ...