So many things in this situation boggle my mind to no end, but the worst of it is Dustin Turpin's decisive inaction to compensate the OP according to their original agreement. The OP has been patient well above and beyond any amount of time that could even remotely be construed as reasonable.
Now, I don't know Dustin personally, whether he has been legitimately diagnosed with clinical depression or anxiety, or what the story actually is, but if he is truly suffering from a mental illness, I can understand how it would cloud his ability to think clearly and rationally, and to start playing the victim, rather than just moving forward with what is really a very simple and relatively easy solution. Just make two more knives and be done with it already.
I understand that Dustin Turpin's knives are very well made and take more than a modicum of effort to arrive at their final fit and finish, but it's not like we're talking about 50 hours of intricate hand carving per handle scale, or 2 weeks of solid 16 hour days per knife. Just carve out some time in your schedule, and finish the knives. Even if it's a couple of hours per evening for the next month, which I think would be a considerably generous time frame for the style of folders in question, it really wouldn't take that much to turn out two more knives and close this issue for good. Is it really that big of a deal to add one or two more folders to the next batch? I don't think so.
We all have to put on our big boy pants from time to time and power through some obstacles for the greater good. Make it happen. Nobody is going to hold your hand or do it for you.
Truth be told, I think Dustin owes the OP more than just the two remaining knives, but all the OP is asking for is simply what was agreed to, and that's really not asking much at all.