2010 Macbook Pro suddenly crashing
The problem you are experiencing is an issue known by Apple. It is an issue that plagued the 2010 MacBook Pro models (especially the 15" versions).
The issue is called intermittent black screen or loss of video.
At one point in time they had a replacement program for the affect models. They have discontinued that and all 2010 models are now in Vintage mode.
Here's a link to the official Apple site talking about the problem.
https://support.apple.com/en-us/HT203554
I actually joined this site trying to find some recourse due to the fact that the product was defective and Apple knew about it.
This doesn't help, but it is the reason for your problem.