Tenant wants to rent out an extra room for a month

[Causalien]

Hi all,

As you all know, I rented out one of the suite of my house previously. What's being a landlord without extra complications right?

So my tenant comes to me and asked if it's possible to have someone stay in the extra spare room for a month or two. (The tenant rented a 2 bedroom by herself). I personally have no problems, but just wondering if I need to sign something with the guy, in case he refuses to leave afterwards. What are my options and what are the potential complications?

*edit: Forgot to mention that this is in BC