thinking the phone's 32gb memory a cheap way of doing it
External hard drives are cheap, USB sticks are cheap.... why in gods name did you decide to use the a phone as a backup device ? Did you not consider the possibility of your phone getting lost or stolen.
Sorry to hear about the photos of your mum, but do yourself a favour for the future and put in place a reasonable backup routine. Its not hard, its not time consuming, its not expensive.
Consider it a lesson learnt that anything of critical importance should be backed up, then backed up again, and once more for good measure. Preferably on three different media (e.g. DVD, USB and external Hard drive). Three copies is the bare minimum for anything of any value, preferably with one copy stored at a different geographic location.
Anything non-critical, two or just one copy.