$54,000 ($810 rent) for 3/1 SFH , but current tenant is a smoker

[Charlotte Edwards]

I have a potential house the seller is asking $54,000 and currently gets $810 in Section 8 rent. He's had the house for 43 years; rented out since 1981. The current tenant (mom and two kids) is a smoker; first smoking tenant.  THey are willing to negotiate, but it's a family member, so want to be careful. Rent can be raised. I know people in the same street, same style house, that get $900-950. 

Looks like the only "urgent" thing, if we let tenant go, is to get rid of the smoke odor. I use a PM so not sure what he'll say about this. Curious on the cost/time involved of cleaning such houses to get rid of the smoke smell. It's 3/1 cape cod style with a basement. 1700 sq feet. 

Appreciate any advice on this. It's our fifth SFH; but I"m abroad and will be relying on the seller and my PM. Thanks!