Shortblade will not give you what you need. if you want melee power for cheap go longblade and get to the Odachi.
and if you have the money for end or intel go Blunt or Axe
i say let him try out sbm and see what he thinks first
3 levels of SBM with a kama Dual gets you 600+ crits. problem with SBM, they start sucking very quickly against any mid to upper level armor, and they are more useless than LBM against hideouts. An awesome beginning way to play as it is a very hard hitting and often hitting weapon.
Of course if you just started in long bladed melee to begin with, and grab a Nodachi, you would have about 85% of the damage of what I am doing, and be 3 levels ahead of me when I convert.