DH had 9 months of aggressive chemo & says the things he learned from it are:
Don't let the water /saline run out, or go for lower water ratios, it burns A LOT. Sorry, horrible one to start with but he is convinced that had he not been talked into 'manning up' and using less water to make the sessions shorter, it would have been a less traumatic experience.
If you can go private or sit in a small room (rather than a large room full of people who sadly were sometimes clearly not going to make it) then do it, whatever the cost. We have PMI but he went NHS as he reasoned the treatment is the same & was bullied by an anti-private consultant. The psychological impact of seeing some people not turn up for their sessions was awful.
You will feel weak and queasy for a day or so after, so well-meaning 'cushion plumping' visitors the same day or the one after are not a good idea. Grandchildren cut through the crap so are to be encouraged!
Don't bother with the cold cap or trying to style thinning hair, just cut your hair short straight away, the psychological damage of longer or more fixable hair on the pillows is not good.
Don't EVER talk about 'fighting' cancer, it implies that people who don't make it are weak.
All 4 surviving cancer family members thought Macmillan were crap - well meaning, but crap.
Sorry these aren't uplifting points, but they are real experiences that can make your mum's ordeal marginally better.
Lots of love & very best wishes to you both xxxx