Try to avoid the anchoring bias of his current pay rate. If you had to replace him and wanted someone of similar skill, how much would have to pay? Offer him that with an explanation, he’s right, wages have gone up lately and the current market rate for his role/skills is $X. You could always back it up with something from Glassdoor on average salaries for job title. Also, don’t forget to tell him you really appreciate the work he’s doing and keep up the good work (with a smile) :)
Lease to someone else that already has a business or is experienced in starting a certain type of business. Don’t risk your profit starting a business you have no passion for or experience with.