You may not like my answer but it’s based on past experience with a lot of young adults under my employ.
Based on the figures you state, I suspect he is already a bit over compensated but reflects the value which you obviously feel toward him, and believe me…I understand that more than you know. I once had a young man who I groomed to replace me and continued to increase his compensation year after year (bonus related) but when it was over, it was over.
I unrealistically expected that my overcompensation would purchase a certain degree of loyalty when “the thrill was gone” but I was wrong.
The concern I have is the age, and lack of maturity and stability at that age. (Marriage, family, mortgage tend to change things.) At 19, there’s still a whole lot of growing up to do.
It’s obviously your business and your call but I think you need to soberly assess how much you can afford, and do not underestimate your end of the deal. The day he walks away, you’ll be reminded of why you can’t go with him.
What is the next step of progress? Ownership? If it were me, I’d offer some sort of stock option or share with redemption tied to present value vs future value of business (annual sales?) and redemption predicated on 30-60 day notice (your discretion) allowing you to find and train a suitable replacement.
I would require it be purchased from his proceeds rather than paid in lieu of cash as it then becomes a discretionary purchase on his part. If he’s unwilling to invest a little “blood”, he’s probably not ready to “progress”.
Sweat equity means nothing to me as it has no convertibility.
BTW, yesterday I just lost an extremely capable 19 year old assistmgr with over a year’s experience who was earning nearly $375/wk as a result of a personal issue (his) which happened on his day off. Can you say “unplanned loss”?
I love working with young adults but I’m well aware of the limitation.