Others have hit it on the head.

There are numerous threads about sub to and many investors believe it is a high risk strategy (especially for seller) and believe buyers who use it “take advantage” of naive sellers.  

Brokers are providing a professional service and facilitating transactions.They give you guidelines on how to and how to not do a transaction and if you follow those rules you've transacted within the law.

So advice to get the house against him and he will move out on his own is HIGHLY unlikely.  

You can use it as a downpayment on a property over $450k and use leverage tax free.

Check out other online guides available here: https://www.biggerpockets.com/guides3.

Do they have any reviews on Google?

I've interviewed him twice on my podcast (once with @Chris Seveney and once on my current show), and I thoroughly enjoyed those conversationss. 

Are there any pushbacks on this deal?  

It's putting out lots of fires, managing finances like a hawk, keeping projects on time, in line and on budget, marketing the property & getting it through closing, and *then* doing it all over again - and that's if you're not doing any of the work yourself.