Of course the father has income; he "sold nothing for something" when it comes to Goodwill. The son has the Amortization = a "useful life" per IRS regulations for taking a bit of the cost each year. It isn't Expense the way paying for electricity or rent is expense; think of it as Allowance. The son is Allowed to write off a bit of the cost each year, until the value of the intangible asset is considered fully expensed. The same is true of that equipment. The son Invested in tangible goods that have a useful life per the IRS, and that "wears out over time" and that is why there can be Depreciation Expense = a little bit each year.

Think of a building; it isn't all gone when you buy it for $250,000. It's right there and has a Useful life. But the IRS acknowledges there is wear and tear over time. That is Depreciation of this tangible asset.

And the son has Debt. Servicing that debt will require payments. That is not Expense. That is paying off debt. That is Liability, not expense. but the cost of being in debt, which = Interest, would be expense. Unless it is prohibited due to specific or certain rules, such as, you cannot be in debt to yourself. That's why @sjrcpa has added that comment.

This might be an event you need to be mentored on.