previous owner has passed away

a coworker recently moved, and was getting rid of some clutter, one of the things she was getting rid of is an iMac that's several years old. it belonged to her husband, and he passed away about 5 years ago, and she doesn't have his login information, but she wants to save all of his files before getting rid of the iMac. one option is to simply replace the hdd in the iMac, but that's a lot of work and it's possible to damage the computer. is it possible to bypass his password, or reset his password without having access to his accounts?