MarkB
Legend
Well, that's up to you as DM - does it take much wherewithall to attune? Maybe he just takes a liking to it because it's shiny.
There is one more possibilty, but it's a bit of a stretch, and a waste of a limited character resource unless you allow him to re-spec later. He's currently 5th level, and a fighter. If he can somehow stumble and chance his way through enough encounters to reach 6th level, he'll earn an Ability Score Increase, which he can use to gain two points of Intelligence.
There is one more possibilty, but it's a bit of a stretch, and a waste of a limited character resource unless you allow him to re-spec later. He's currently 5th level, and a fighter. If he can somehow stumble and chance his way through enough encounters to reach 6th level, he'll earn an Ability Score Increase, which he can use to gain two points of Intelligence.