This will be my first post on a stack exchange site, so please excuse any mistakes I make if possible.
[This first paragraph is backstory of sorts; not really important]
My father's phone's SD card recently became corrupted. Neither him nor I know the reason as to why. I did not know what was on the card, so I made no attempt to immediately rescue any data. A while later, his phone began spontaneously rebooting for no obvious reason after being used for a short amount of time -- again, neither of us know why this has happened. I afterwards found out that this SD card contains vital information relating to the medical treatment of a family member.
Assuming it is possible, how would I go about recovering data from a corrupted SD card which was previously formatted for internal storage without having the phone on? In this case, the phone is able to boot into recovery fine, and is able to actually start up for a short period before it appears to crash.
The phone is a Blu Life One X2 64gb internal storage with a now corrupted 64gb SD card formatted as internal storage.