Hi,
I feel your concerns. I have been on end stage since December last year and got a catheter sometimes in February.
Usually, it is very emotionally challenging to the patient and the family but like you said you must show courage and be strong for your mum. She will draw encouragement from you.
Please let her know that the catheter is in her best interest and that she is not all alone in this challenge. Several people you see around are "carrying their cross" silently.
Be strong and very courageous.