You have a bunch of things to learn about and might want to find someone to do this work for this year for this person and to mentor you at the same time. Let's review just a few things:

"and take it out of the gains from the sale of the homes."

Nope. That isn't part of the Costs of the homes.

What this owner pays themself is a Draw; they took capital out of the business that already is their money, anyway. In this arrangement for this entity type, they are not an Expense to their own business. That is not Salary, so you would stop using terminology that does not apply, to avoid confusion. Salary implies "flat or fixed payments through payroll." Salary is a type of Wage agreement and Wages only apply in a Payroll activity. That's why you were asked about the 1099-NEC for the assistant.

See this: https://turbotax.intuit.com/tax-tips/small-business-taxes/penalties-for-not-filing-a-1099-misc-irs-f...

The assistant falls under what likely is Worker Misclassification. You would have to understand the IRS requirements for how to determine if that person is Employee or is Independent Contractor. This includes evaluations such as whose equipment (computer, phone, etc) is used by the Assistant (their own or your flipper's) and who sets the work tasks and work load and supervises and who sets the work hours and who is at risk if something goes wrong. For instance, if the assistant is independent, and something goes wrong, they would be personally liable financially and professionally. An example of this would be Insurance or Bonding or Property-related issues that the assistant was responsible for. If something has to be resolved, especially some sort of fine or penalty, and the assistant was responsible for the task but doesn't have to pay, then it would be described that their "employer" paid as part of the project. You need Payroll when there is an employer-employee relationship for the assistant.

Deciding to file to have the LLC treated as a Corporation means everyone is required to be on payroll and there are a lot of other considerations. This is not a light decision to make. Again, get someone else to review this, if it is not something you have helped with in the past.

You asked this in an old topic elsewhere: "how do I report his expenses in running this business"

You need to understand there are very few Costs associated with running this business. Office supplies, phone, etc are Business Costs. Nearly everything else is part of Property Improvements. Each expenditure (not Expense) that is directly applicable to specific property, or allocated across them (such as Dumpsters or equipment rental) is part of the improvement costs. They are not on the tax return as Cost until the property sells; that means some properties will be owned crossing the year end, and that means the Cost is being Accrued as CIP (construction in progress) and held as part of the Asset. For the date of Sale, the Asset costs are computed against the Gross revenue, to see the profit on that specific piece of property.

So, whoever is doing the bookkeeping should be doing all of this, already, and Correctly, for the tax preparer. You would not be making any of these actions part of the Tax return adjustments. They are the ongoing operational data. You would confirm they are doing it right, though.