Hi Emmaround,
It sounds like a tough time for you and your mum, sorry to hear that. I guess after being on this site for a while, I've come to realise that everyone experiences a lot of fear in the beginning, and everyone wonders what to do. So you're not alone, and hopefully coming online here will help you feel less alone.
Maybe talk with your Mum about just dealing with things in "bite size chunks" at this stage. Just take each thing, each day, one at a time. Find a really good person in the treating team that you can talk to - I"m sure they will have suggestions about what might help both you and your Mum. They have some great treatment for pain, and they will try to help.
One thing I"ve learnt is that nothing ever stays the same - everything changes. So for me, each chemo was different, each time I went for radiotherapy was different - sometimes I expected it to be awful and it wouldn't be too bad after all. I learnt to not look too far ahead - just stay in the moment and deal with the moment.
None of this is easy to do but you have lots of love and strength combined, and you will find your way through this. Just being there with your Mum, and sharing some of your strength and courage with her - your willingness to hope for the best - these are the gifts you can give her...it mightn't take away the pain but it will help her feel better within herself. Take good loving care of you too Emmaround...
Zen 🙂