Dad Staying not on lease!

[Jennifer Sleider]

My tenant moved here from out of state. Her husband and father came to help her move and stayed a couple days. Her husband will not be living with her full time as he will be primarily living out of state, just visiting often, but I told her that he had to be on the lease. Her father though, she just told me is going to be living there a month, which is in violation of the lease. My lease states

The only person(s) living in the Leased Premises is/are: (the husband & wife) 

• A.Any change in the occupancy will require written consent of the Landlord and may be subject to an adjustment in the amount of rent. 

I need help on how to address this!