Don't know how to help.

My friend has been off work for 15 months with depression and anxiety. She is constantly having her ad meds changed by GP and has had 6 weeks of telephone counselling which has now ended.
I text often asking how she is and have popped in to see her a few times and I'm very worried about her. She says she has outlived her usefulness and is awake all night then sleeps until lunchtime. She just watches TV all day and now won't leave the house without her DH.
He is lovely to her and works a demanding job so the housework has slipped. I don't want to hurt her feelings by suggesting I help with it but at least it would be something I could do. She is usually such a funny vibrant person and it's so sad to see her with all the stuffing knocked out of her.
Often we arrange for me to visit and she cancels at the last minute. She has isolated herself and I know that apart from DH, I'm probably the only person persevering. I have 3 children under 9 and am pregnant so not able to go round as often as I'd like. How can I help her? AIBU to think she'll be like this forever now?