In most places, a verbal rental agreement is month-to-month.

Given the last commenter's advice about waiting for someone with experience to chime in the first time, that someone has to take a risk... the issue is that there is a high likelihood it will be either a loan-to-own lender looking to obtain functioning properties or a scam.If it's true, they would have SO much business; whatever funds they have available, they would be empty in 1 month or less because that would be the best deal in town if it's true.

However, my concern is:  would my parents be committing fraud by getting a HELOC, and then turning their primary into a rental just a few months later? 

To start it, will need to get the utility gas service turned on and then perhaps get a plumber out to start if and checkout everything.

If they did without propane for several months, not sure they'd notice the lack of hot water.

That increases my monthly cash flow and it boosts the value of the property to increase my equity.The downside is that it can take a lot of work, time, money, and patience. 

Project is about a month out from completion so I’ve been thinking about the refinance part of it.

@Mike Grable  you could just have a month to month lease.   

This means, in effect, that he has not paid his rent for this month, July 2024.How can this happen?

I have seen more and more people put houses that should only be a long term rentals into service as a STR, as well as paying prices that will not cashflow.