Hopefully it doesn’t come to that, but he does have two evictions on his record already so it’s not out of the realm of possibility.Thanks @Kathleen Leary for your suggestion for the lease.  

And if bridge loans is the best for this strategy, what tips would you guys suggest when using it. 

Any suggestions I appreciate in advance.Worst case, I'll just create something for him and walk him through things as he goes, but I'm thinking, why not document it for us both (no plans to publish or anything though)!

.- I would highly suggest you plan on using a property management company.

My suggestion is to get them going in that route, buy a house they like, can afford, and see themselves in for 7-10 years + and then get going with paying it down.

But there is precedent for what I'm suggesting (as you are seeing from other commentors and from very large brands like Vacasa and Evolve) so presumably this is possible.

I suggest buying real estate inside of and outside of your IRA or better yet qualify for a Solo 401k then you don't have to worry about UBIT on leveraged real estate. 

What or who do you suggest I speak to or learn from to better understand my options for mortgages?

If it is only one flip for now, I suggest you find a CPA just to advise you on State filing requirements, ensure you are claiming all write-offs and issuing 1099s, etc.

I want to get some suggestions from experts on what option worked better for them and why?