Give it time, it'll sell. The BBQ is a good idea, and personally, I would not believe everything the realtor tells ya. Turn on the potential buyer to the BBQ and a "salad" from you neighbors garden perhaps, then hand them a pen 20 minutes later.
Seriously, there are plenty of people pulling down enough money to afford your home that have no issues with caregiver medicinal use. And to tell you the truth, I am rather surprised all these potential buyers recognize the smell.. but like I said, that's according to the realtor, hopefully she isn't spilling the beans about the neighbor..
Something doesn't quite add up to tell you the truth?