When someone says "No Spoilers" they probably don't want you to mention the Balor.
It really isn't terribly important to convert every little thing, like you would a 2E module. It may feel a little clunky, but most stuff can be run as-is. If he can't find a conversion for something, he can either wing it or just use it as it is written and the players probably will never notice.
I would recommend he add some of his own flavor to the module, because some parts can get repetitive (especially if you don't meet very often).