Encourage her to take up some hobbies, do a course or join some groups - my mother joined a gym after my father died - she loves it...
My friend paid for her mother to attend a book circle - a retirement gift - she loves it and has made lots of friends and is always busy reading the next book ready for their meetings.
My mother lifts weights, walks on the treadmill, has a coffee with some friends after their workouts - and she's getting younger and younger...
We often joke that she's stronger than all of us...when my brother was moving house he mentioned that Mum was helping...I said, "make sure she doesn't overdo it"..He said, "No, I'll just get her to move all the heavy stuff, then I'll run her home"...He was joking BUT, she is very strong. While her peers are falling to pieces, she planning her next workout routine.
Mum was never able to "do her own thing"...she married at 21 and had 5 kids - my father didn't like her being independent - he didn't want her to drive/work or pursue her interests...this was a common attitude in the 50s...your place was at home and your husband was supposed to support you financially...
Also, the last few years of my father's life he increasingly wanted to stay at home...I know Mum felt like a caged lion over those years - she wanted to enjoy herself after years of raising kids. It was her time in the sun. (she loves kids BTW)
I know she's loving this stage of her life...we meet for lunch or dinner regularly, chat on the phone and sometimes, we holiday together - last year we spent a week in Port Douglas with Mum and my older sister. Mum has travelled quite a bit over the last 10 years - she does very well on our frequent flyer points!
I would find it hard living with my mother again - we're very different people but, we really enjoy the time we spend together. She's joining me in Japan in April and is busy reading up on Japanese culture etc.
So, she has a full life - gym M,W & F, babysitting Thursday & the cinema on Tuesday...on the weekend she catches up with family.
My brother and his girlfriend threatened to derail Mum's life with unreasonable babysitting demands - as a family we were forced to intervene - it caused ill feeling but, this is Mum's time - she's raised her kids.
So, she's now an independent, active woman on a mission to experience as much of life as possible...we all say the day we call Mum and invite her to lunch and she says, "No"...we'll know something is wrong! She's the first to grab her coat and out the door!