Tenant wants to move her adult son into the home. What should I do?

[Melissa Faraias]

Hello BP community,

I am a newbie landlord and I have rented one of my units (SFH with 3 bedrooms/2 baths) to an older couple and their adult daughter. They have been wonderful tenants so far. The mom recently told me that her adult son is moving to the United States from Dubai and will be looking for a job here. He would like to stay at the house till he finds a job. His wife and child may be moving as well in a few months. He just got a social security number and has signed the lease. I wanted him to fill out the application and do a credit/income/background check but I'm not sure if he will pass since he has no history in this country. I do not want to reject him based on those grounds and I am considering increasing the rent by $100 a month and letting him move in. I did tell the current tenants that if the wife and child move in, it will be an additional $100 per adult and $50 per child to account for the wear and tear on the property. Does that sound reasonable? Should I have the current tenants sign some sort of document taking full responsibility for the family that is moving in? Thank you for any advice that you can give me.