Adding two tenants to current lease.

[Kiara Moon]

Hi! 
I rented my home to my boyfriend 21 year old brother- in order to move in his ( my boyfriend) home with our child and see where it can go. I gave the brother a “break” on the rent where I may make $2,300 a year off the property. I made him sign a 12 month lease with renters insurance. The lease started November 2021. He is current on rent so far and no issues but, I was asked if my boyfriend parents can move in with him. I wouldn’t have an issue with that if the rent is increase and everyone is on the lease. I live in NYS what is the best way to tackle this without so much risk to me. They also have animals that I really wouldn’t want on my property. I assume I have to charge a fee for that as well? I am so lost on what to do. 

current rent is way below market value for a whole home as well.