Your best bet is to do the human thing by helping this person find another space, but also do the correct business decision which is to terminate this business relationship. 

We are constantly building and maintaining relationships with key brokers, property managers, other local property owners, lenders, etc.

  ( or any other work in the building)  I believe the relationship between landlord / Tenant needs to be protected. 

All it takes is one estimate to be off and a relationship issue develops. 

Estate likely gets to take the deduction and probably should reimburse you assuming you have a fiduciary relationship.

I'm not sure what your relationship is with him business-wise or if he is a seasoned hard money lender but generally 10 % in thiscurrent market is good.. for investors the comparison is always the stock market or CDs none of them are bringing in anywhere near 10 so to diversify and get 10% from Real Estate..with a secured position... estate is great I would actually offer him 9 to start. the contract should be written up by an attorney after both of you agree to terms .you said you're doing a flip ?

He now says he wants to "train" me to manage his properties, as if it would take a genius to pick up a phone and start building some relationships with decent contractors. 

As usual, personal relationships are the most important.

I can understand not wanting to mix real estate investing and the relationships that you have with people at your church.  

A lot of people think theres a lot of turnover with M2M, but the truth is if you have a great rental and have a good relationship with the tenants they stay longer anyway.