I ended up installing all the .dll's and .net frameworks associated with rom hacking before ever getting XSE so I have no idea whether having them or not changed anything.
Is he using a Mac? If he is then he will have to use Wine so it can emulate a Windows OS. If he is using a Windows OS then it will be more complicated. Does he receive any message about the crash when it happens, like a runtime error or something? If he is getting it some sort of information then I would try going on that. It could also be a permission error but frankly I have absolutely no idea :P
I don't think it requires any specific .dll or .net since I can't remember XSE crashing for me since getting it years ago (apart from changing the AutoUpdate=1) even though it was one of the things I downloaded first. I'm not very experienced when it comes to dealing with a serious internal problem like that nor do I have an insight into what it needs to run - I'm just throwing ideas into the air right now haha.