He has an AMD card and from what I’ve read can’t implement physix very well if at all. It drops your FPS so low that either it freezes or crashes. Very common issue with AMD Radeon gpus. A lot of peoe have been turning the physix over to their CPUs to handle the physix as a work around where as others have done other things that I can’t remember off the top of my head.
If his physix are on the lowest setting theoretically he should be fine. So it is highly possible that there is another issue going on.
And I do believe that you can disable several physix features manually through deleted files and whatnot and changing configurations around but I doubt he needs to do something like this.
He should also check is control panel for his graphics card and change the physix there just in case it’s not taking effect I’m game. As in it may be hardware instead of software problems.