It is possible that he doesn`t interesting to communicate here. He left contacts in the first post.
I don`t how the casino works, but if he is telling truth - the ROI is about 3 years is good enough. But it must be researched seriously before deal, with some financial and gambling specialists. The same time i think that it is possible to spend this money more clever - get a good dev team, create a new casino and promote it. It is possible that it will take more time, but i sure that it will be cheaper and you willn`t have any doubts in the deal.
This is generally not worth it even if the OP is responsive, the asking price of $1,500,000 is way too high. This is the site that one would use extra money to inquire about through the tech experts on the internet to verify that the claims of the OP are true to some reasonable extent.
Besides, can you imagine, a casino site garnering as low as 47,259.96 in a whole half of a year, how many years would the buyer run it before such a huge asking price and the investigation amount be made back? It's a bad business in my opinion, and who knows why someone would want to sell a working casino.
If the OP tell us the truth - 3 years ROI doesn`t seems a big time for ready business. $47,259.96 - it is per month, if i understand correct. The OP tells us:
So, the ROI is 3 year with several months.
But i don`t think that it is a good idea to spend such sum to get online business, it isn`t the same as to buy an offline project.