If your photo of the bowie with the tiny stub tang in the larger handle is what it will be ....
NO it is not strong enough.
To be properly done the joint of the blade to the frame tang should go 1" past the guard, and on a sub-hilt, 1" past the sub-hilt guard.
Tell the maker to redo the blade with the tang going through both the guard and sub-hilt at the width of the ricasso plus 1" longer. From there he can taper it down to whatever he wants.
If he balks, tell him you insist. If he starts moaning about the "loss of the steel", tell him that his error is not your responsibility.
Lesson to learn - NEVER pay more than a 25% deposit on a custom order. Many knifemakers don't even ask for that up front.
If this doesn't get resolved, send me an email at
sapelt@cox.net