If he's talking .graal files I doubt Gonstruct will open them. Best bet is to run a VM with Windows 7 or older to view them, and you can also convert them to NW after you open them--just resave them as NW.
Alternative there used to be a Graal->NW converter tool. I think I may have found it but I can't vouch for how well it works. I did obtain it from the official forums so it should be safe at the very least.