Problem: I think you might be right but according to Wikipedia LLC refers to a State definition of Limited Liability Company (Wikipedia 2022). It seems like it is essentially the same as a Limited Liability Partnership which is what is discussed in the text (Yates 2019).
My question is if they create a promissory note this would settle the accounting issue and ensure repayment of the loan, but are we just disregarding the contribution of Jay's father? We don't know exactly how much renovating was required but with the price of lumber these days it could very well have exceeded $20,000. I know we have to make a lot of assumptions in this scenario, but don't you think it would be better to include the two dads as limited partners?