First thing to try,Close SU and Layout, Find the install file .exe, probably in your Downloads folder. Right click on it and choose Run As Administrator, then when the option is given select Repair and follow any prompts.

Well, SketchUp 2015 doesn't support operating systems that are newer than it is. If he's updated the operating system, it's no wonder he's having problems. The solution is to update SketchUp. Keep in mind, SketchUp Make is for non-commercial use only. If he is using sketchUp at work, he needs to be using Pro. You do, too, if you are using SketchUp for anything other than hobby use. Your profile indicates you are using Make.