Call the cops saying they are running a drug operation and they get arrested.

A friend of mine is a detective on the police force, and he cases out drug, prostitution, human trafficking, and organized crime.

If its not problemmatic, then I would have ZERO issues with it and let the person who is a good tenant stay and not have to upend their life to move out especially with declining health.Now if the kids are drug dealers and have other people coming and going, compeltely different but if its just them - I would have zero issues with it.

I've had similar issues here in Chicago with Squatters and drug dealers.To do a 203k, you need to live in the property for at least a year so technically, that wouldn't be an option. 

If that were true, then a landlord would not be able to evict for , let's say, illegal drug activity or loud parties , for example.  

If the house was used for drugs, expect unwanted visitors seeking to buy drugs for the next couple of years9.

There's so many things that can change the dynamics and attitudes like partners dying, getting married, getting divorced, having kids getting addicted to drugs/gambling/porn/anything, not pulling their weight, wanting to sell, stealing money, getting cancelled form some social media post, and the list goes on.

So, yes its my first deal in America, yes the photo is of my only surviving son.The picture of your 11 year old with cash bills spread out like a drug dealer sucks… with or without a back story. 

In her personal life, she is involved with someone who deals drugs, as they do drugs and are involved in illegal activities.

If you do that, or the option with your brother, have a lawyer draw up contracts that account for everything that could go wrong (death, drug addiction, marriage, divorce, lack of effort, someone wants to sell), and that clearly spells out ownership.