Hi,
I'm sorry to read your message about your mom. What to expect really depends on what her chemo regimen is and how advanced her cancer is. My advice is for you to meet with the infusion nurse manager to talk about the actual treatment and what side effects to expect. Stage 4 sounds so horrible, but all I think it really means is that it's spread to other organs and can't be removed through an operation. It's not necessarily an immediate death sentence.
My mom (62) was diagnosed in Nov 08, had surgery where they removed what they could (part of her liver, entire gall bladder, several lymph nodes), but was left with the cancer and has been on chemo since Jan with a one month break in June/July. She just started back up this week. She regularly takes a blood test called CA19-9 and the results trend helps her and her doctor know about the progress of the disease. Her chemo is Gemzar/Xeloda which is a popular combination for GB cancer and she's had only some gastro effects - but nothing like hair loss and constant nausea. She recently finished radiation (5 weeks) and it made her so exhausted she couldn't get out of bed some days. She's fine now though and her numbers are back in the normal range for the CA19-9.
Everyone's case is different, but I hope that you will persevere and encourage your mom to fight. The dr can prescribe something to help her with her appetite if she needs to get hungry.
Feel free to contact me privately if you want discuss more of the specifics. I remember feeling pretty lost in the beginning and it seemed like no one shared our exact circumstances. I hope you can share good news with us in 6 months too.
Wishing you and your mom all the best,
Marie