Will courts evict in the winter?

Sounds like your parents actually want to sell at fair market value, but think that if appears as if they are selling for less you will somehow be able to obtain a larger loan in 13 months.

When you buy a property that cash flows (which they all should) you should appear BETTER to the bank. 

Well Don’t count on the lease to protect you in court .

@Ernesto CorreaIt appears that HELOC's interest rate is hovering around 6%.This interest rate seems very attractive to most alternatives.Regarding the deduction for tax purposes - Previously, you were able to take out a HELOC and the interest expense was deductible aslong as you itemized your deduction.

How well do you know the local court system?

He can not back up out of contract when it's time to close - you can take him to the court for "specific performance".You have the right to get out of contract after the inspection done and get your EM back if any was deposited.

Implies a 6% interest rate.What you propose may appear easier, but the math doesn't check out...

Their SEER (~23) and HSPF (~10-11) ratings are behind the industry leaders.Their Infinity Line looks very much like other house brands manufactured by Gree (appearance and specs line-up) and boast/claim a SEER ratings of 30-42 and HSPF of (10-15) ... though their noise rating are still akin to a loud dishwasher.  

Why would you as a seller create what appears to be a fire sale of duplexes in the area????!!!!