Addendum to sublease?

[Carrie Nevins]

I have a tenant who is becoming a very large headache. He agreed to pay $900/month alone, yet every month has another sob story about why he can't pay on the 1st. His lease states that subletting is not allowed, but I sent an addendum allowing him to sublet to his friend. His friend does not help with lawncare, has had an unauthorized pet on the premises, and has painted a room (causing damage to the floors and trim) which also violated the lease agreement. Because he and his friend cannot pay rent on time, he just informed me he is going to find another person to sublet to (along with his current tenant) 

Can I make an addendum that no longer allows any future subletters? I am afraid to allow yet another person in the house who is going to cause damage, which I will just have to eat because they aren't paying any security deposit. Thanks in advance