I have a unique opportunity but I'm unclear how to approach it.

Owner runs a tailoring business doing about $550K in sales and $190K SDE with 7 employees.

It's a small operation, but it intrigues me for two reasons:
(1) roll-up potential being such a fractured space;
(2) most importantly, he wants to stay on as the Operator.

He wants to sell while still having a "job". He needs something to do but at 50-something, he doesn't want to work for someone else or start a new business. Reason for selling is primarily because he is going to have a major surgery that will take him off his feet forredactedmonths and he doesn't have someone to replace him. I was clear I would not be in the day-to-day, but open to jumping in when needed for that period. I think we can also hire someone for a manager role, even temporarily.

I think the best structure is to have him be operator with a salary while retaining some ownership. However, what price, what salary, what ownership stake... I don't know. Need to balance the risk in case he doesn't continue operating things. I'm open to exploring this all within a seller note or some other creative structure that balances such risk.

Thoughts?... How does this work as a nice simple investment that protects me given the risk a roll-up may not work, while also giving him enough value and a potential second payday when he officially retires?