Inherited Tenants running a business in property...

[John Ringgold]

In a few weeks we will be closing on a duplex where both sides are rented by one individual with a month to month lease.  The young lady is a nurse and is using the other side to "sub-lease" to an elderly person where she can provide care for them by being right next door.

We are working on our new lease as this will be our first rental investment purchase.  The current landlord was okay with this arrangement, but we aren't sure this is a good idea.  Subleasing and running businesses don't seem to be suggested practices with leases.  

Would you allow this arrangement?  What are your thoughts and concerns?