While doing cooking for the first time in a while can be draining, it's a form of concentration that gives specific rewards. It's meditation that provides for the body as well as the mind.
Her mum is right, same reason why you should exercise, in the end the only one you have to rely on is yourself, you only have one body, one chance at life.
I'm glad that she's taking steps back from the abyss. Soon she'll feel the warmth of life upon her back and be able to smile freely, daily. I can't wait to see that smile.