Your lease probably specifies the residents must comply with "quiet enjoyment" of the property. 

Quote from @Hunter Hanlon Taylor: Investment Info:Single-family residence buy & hold investment.

Quote from @Irina Badal: I heard for anonymity purpose it’s advisable to set up a personal residence trust.

For the son to qualify for the $250k exclusion, I believe he would most likely need to meet the ownership and use test, meaning he needs to own and live in the home as his primary residence for at least two of the last five years before the sale.

It most likely won't help them in this case but let's face it - they're not big on resolving their own problems especially when you're accommodating them.The longer you allow them to live rent-free with no solution in place, the longer they will do just that.

I'm very new to investing and weighing which options would benefit me the most.Option 1:  Use the cash as down payment on another primary residence and rent out the current.

This is such a great way and solution to ending homelessness. 

It was my primary residence for two years before I turned it into an investment property.

HELOCs are fine, but keep in mind that you really only want to use 50 percent of less (each) of your available equity just so you aren't creating a problem that you can't solve later if the value of your personal residences fluctuates.If you both have W2 jobs though, have you looked into getting qualified together and just getting a loan, 10 percent down each?

That doesn't mean you have to file bankruptcy, but you do need to know there are better solutions than Subject To when in foreclosure.If you sign a deed in lieu, that means you will no longer own the property and will probably never be able to buy it.