I concur that it is a lot of work. If you have the space, the welder, the ability to weld cleanly and quickly, AND the time, then this will be a great project.
Otherwise, NO.
The cab has so much rot that it will take you every weekend for a year to strip it of parts, remove it, cut and re-weld, and then re-install everything.
And in the process, bolts will snap, pieces will break, important components will fail when you put them back together, and then you have an expensive collection of parts. Then you won't have the money right at hand for new parts, and he will lose interest due to the wait, and then you'll have a truck filled with a huge amount of time and disappointment.
If you want to use a truck project to bond with him, get a newer one in better condition. Rebuild the motor, or transmission or both and have it running in less than six months. Repaint it a distinctive color - or colors. Then when he is ready, or along the way, get another Slick in better shape, especially from the SouthWest, and have it shipped home to work togther on it.

Or take him target shooting, and learn to reload 9mm ammo. Buy him a little 9mm or 380 pistol or even a .38 or .357. Reloading is cheap, you can get nice equipment for less than $250, and reload a thousand rounds for about $100. So, for just under $1,000 you can have a complete hobby - pistol, reloading equipment and the ammo.
Or take him fishing.

I would say put the bonding time ahead of the truck.