Man, this is a hard bone to gnaw...
I bought my first bike after riding maybe an acuumulated 15 hours, on someone elses bikes, totally offnroad, dirt trails, vacant lots, construction sites... etc.
I was not 26, at that time I was 18 when I purchased, but did the riding prior... street riding is totally different, you get run over/into when you err.
That said, I didn't buy a "streetbike" until I had mastered the control, lack of control, idiosynchrsies, and many crashes into the dirt, well prior..
Seems the steps on bkike size and expectations, as used in many countries for "escalating bike sizes" based on time and usage have all been lost. I see it every day here, people buy a GPZxxxx+ bike for their son at graduation, and I say the next thing may be a funeral....litteraly, I see it.
All I can say is, sell the bike when fixed, toss that money on a "dirt only" bike, not to exceede 400 cc, make it a requisite to ride, and MASTER that machine completely, and then, sell it, and let the kid buy his own...
But then, at 26 years old? I'm saying step back, there is little you can do to "unlearn the stupid misconceptions" a person has for what it takes to responsibly stay alive, riding daily, on a road.
Education only works when those being "educated" can viably show, without a doubt, they comprehend, and can deliver the product of the effort.
I'm sorry, but somewhere, something is missing in this process so far, so many crashes, by soo many inconsistant behaviors, elicits this young man needs to stay off 2 wheels... until a point comes when he understands the outcome may result in death.
I'm at a point, where I debate this in my own mind, about passing bikes on toy grandson... before that day comes, I'll place a ladder next to the garage, and tell him to climb up on the roof...nthen coerce him to jump off... I'll work hard at it...,,,,, but if he even considers it, he ain't riding..