Compelling personal reasons

I’ll try and keep this short, I attempted to attend university 3 times over the years but had to drop out due to mental health reasons which were caused due to my mum’s declining health and me having to look after her etc. Unfortunately she passed away in 2019 and 5 years on im ready to apply for university again.
However I know I’ll need to apply for compelling personal reasons to gain student finance again but I need some help in what to send them to gain finance back for 3 years.

I imagine I’ll have to send the death certificate but would a signed letter from my GP work as well detailing my mental health issues from over the years?

Any help would be appreciated thank you.