Of course wait until the politics hashes out, but it is a good business if done properly. Either you need a great location with a lot of tourist traffic, or very cheap rent.
Also good genetics are not easy to find, so make sure he's growing top shelf, or the shop won't do well. It's pretty easy to find good weed online for less than half price of the shops, so you would need to stand out either with great weed for tourists, or great prices for locals.
Hit me up if you need an independant tester. I'm a experienced grower and 40 year smoker.