How about explaining to him that they've been in business for a very long time. If they made junk, they wouldn't be around.
Show him a RG3120. Mahogany and maple top. Just like a les paul.
Show him an Iceman PS10. Workmanship that rivals any Gibson or Fender.
How about the fact that some of the greatest shredders that ever lived, used, and still use Ibanez.
Ibanez guitars would not have survived all these years virtually unchanged if they were crap. Some of those old RGs from the 80s play amazing! frets worn and everything.
I have never even seen an Ibanez made from plywood. Basswood, and Mahogany are their main woods I would say.
Tell him if you get a Les Paul, you'll have shoulder and back problems 'cause they weigh a ton!
Ever play an OLD strat? GEEZE! that curved neck fretting out all over the place. or very high string action. not exactly a wizard neck.
I'll take a $300 used Japanese RG550 over any les paul or strat any day.