The problem with the new rules is you cannot restrict anything down to 35kw now. You can only restrict down from less than 70kw. The FZS600 is between 95bhp and 99bhp dependant on where you look. Unfortunately, even 95bhp equates to just over 35kw so out of the game now for new riders until they go derestricted.
How old is your nephew Zarni? If he is over 24 he could have gone straight for the fully derestricted licence. I am guessing he is not, but is over 21. Fortunately my eldest passed his test in August at 17 so he gets to go fully derestricted in 18 months time whilst he is only 19. New riders now can't get there till they are 21 at the earliest.