It is not a revenue but rather a reimbursement/off-set of an operating expense.

If you don't think it will fly, tell them you will reimburse their selling agent commission and/or closing costs when they sell.

You just have to come up with the funds for each stage of the renovation which they reimburse you for. 

Generally, the hard money covers 80-90% of the purchase price, you can roll in the closing costs and get reimbursed for the rehab money after inspection on a draw schedule.  

would I be entitled to reimbursement from the lawyer for legally advising me in the wrong direction?

Some loans are insured and the lender is reimbursed a certain percentage.  

I know mine must reimburse me for any fines or fees from the city (leaving garbage cans out, not mowing lawn, etc.) or HOA violations.  

In pulling some records from the clerks office, it looks like you got a reimbursed your $3500.

They are family and if they loaned it to you it was more on a personal level and believe in time you will reimburse them.Also your success is bigger and more important than the money they gave you.Just my thoughts, hypothetically speaking

Would let him know that any ethical-moral obligation I felt to let him retrieve his stuff from his mother's place went out the window when he opened up a meth lab in there and that he may retrieve his effects, under supervision, after he has reimbursed you for lost rent and the cost of rehabilitating the unit.