I've had chemo, so this is from my own experience.
Food:
Steroids made me very hungry, moody and bloated. Not sure if your relative will be given any, but if she does make sure she takes lots of food to the hospital to snack on.
I didn't lose my appetite, but did get very bored of hospital food. So if you can take food in for her so she's eating different things that will help. You'll have to ask the hospital if there's a fridge to keep food in and warm it up, if there isn't I'd just take something in when you visit her.
Personal hygiene in hospital
I found baby wipes useful to give myself a freshen up. Take small bottles of shower gel, shampoo and conditioner in rather than big bottles. Also some hand cream, face cream and body lotion, as your skin gets dry. And lip balm if she's prone to dry lips, and cold sore cream if she's prone to getting cold sores. And also remember the other usual toiletries.
clothes
Make sure she takes enough nightwear and knickers for each day, so she can freshen up.
entertainment
Hospital and chemo is very very boring. Make use of the family rooms, and walk round the ward and other areas. All you have to do is push the drip stand, takes a bit of getting used to but it's easy enough to walk around with it.
iPad, downloaded with prerecorded programmes, as there might not be any internet access.
Magazines, books, puzzle books ect.
If she knits or does crochet, or cross stitch tell her to take that. If she doesn't learning cross stitch or something keeps you occupied for a while.
Tiredness
Rest and sleep. Try not to do too much, it's normal to be tired during the chemo and for a few days after. She might find that she's exhausted after it, then feels ok until the next round of chemo.
feelings
Treat her normally, and try to act normal around her. I felt like I had to hold it together as some family members became distressed when they visited me in hospital. If you and your family need support speak to your GP, or try and get some counselling.
She also may become depressed and anxious. This is normal. Make sure she mentions it to her specialist nurse/oncologist and ask for counselling. They'll probably monitor her mood throughout treatment.
Alternative therapy
When I was in hospital I could access treatments such as reflexology and reiki. Ask the specialist nurse what services are avialable.
benefits
Speak to the specialist nurse to see what benefits and grants are avilable.
Hope this helps, and she gets through it ok.