Tenant Moving Out Due to Deployment but Leaving the House to Her Son

[Jack Quin]

Hi,

I want to get your inputs on how to handle this situation. 

My tenant, a single Mom, had rented my rental for almost 2 years with her son and couple of grand children. She is working for federal government and had deployed out to another state (she is not a service member by SCRA). Her lease is one year and almost time for renewal. Her deployment (not sure the deployment is short term or long term) was last month and asked me to allow her son and grand children to stay and she will continue to pay the rent. I said yes since her lease was almost over. Now it is time for me to decide whether to renew her lease. I don't really want to since she were always late for rent payment. She really loves my house and maintain it well. But I don't think my house fits her budge since she is really struggle with rent payment although my rent is below the market (I do plan to raise my rent gradually). 

I don't like this arrangement that she is in another state but paying rent for her son probably because her son is not going to be qualified to get an apartment. How do you handle this situation? What reason would you give to the tenant for non-renewal? House is in Maryland.

Thanks.