I think they want him to have skin in the game. 

Most lenders will not allow a subordinate lender without some skin in the game (at least 10% down from the borrower). 

I am thinking I would want some skin in the game as well to make them feel more comfortable.

I have a working DST right now with Healthcare Realty Solutions, great return, check hits every month, I like the fact that they are the sponsor and broker for the deal "have skin in the game", I also like that it is a gyno clinic in August GA tied to a medical school, seems pretty stable. 

I want them to have $3k or 4k out-of-pocket to have some "skin in the deal."

Essentially because you don't have enough 'skin in the game' as determined by the lender you have to pay MIP an insurance should you default, which would be less likely if you had a higher down payment to lose in the game.

They have more skin in the game then you do.Make sure you get clear title.

.- Have some skin in the game.

Pro tip: Even though you can put no money down, you should be offering money down when you offer (even if it is returned at closing) so you have skin in the game.

So I require skin in the game (average is 5% to 15%) to offset this.