It's really bad to hear that
i thought your mum felt better
We are here with you sis @Maris i know it's a tough situation but as muslims we know that illness is a test and a purification of sins.
Sometimes i feel like i want to get sick and suffer on Earth than on the other life.
Duaa;
Rabbana 'atinaa fid dunyaa hasanat wafil aakhirati hasana taw wa qinaa azaaban naar.
Oh Allah! Our Lord and Sustainer! Grant us good in this world and good in the Hereafter, and save us from the Fire of Jahannam (Hell).
For your mum;
'As'alu Allah al 'azim rabbil 'arshil azim an yashifiki.
I ask Allah, the Mighty, the Lord of the Mighty Throne, to cure you. (Recommended to repeat seven times.)