Hi Leslie, im sorry to hear bout your mum, my grandad was diagnosed a few months back with this cancer too. his is also inoperable so he's undergoing chemo. He keeps losing weight as well but my grandma tends to get him whatever he feels like when hes hungry, and the doctor has told us its trial and error with his diet. Apparently semelina pudding helps and keep the imune system up and dark chocolate is good as well because of the coaco.
I recently bought some essaic herbal tea but he cant take it till hes finished the chemo, thats also supposed to help fight the cancer.
I dont know if this is any help, I can try to find out more when i go and see him.
Hope your mum starts to put more weight on and this is helpful.
Ailsa x