Colombo has no proper night life in terms of clubbing. There are casinos but not what an Indian guy expects: dance with girls and especially intimately if you know what I mean.

They expect western type of night life.
99% of Colombo nightclubs are desperately waiting for a girl to walk in, and if anyone goes there by mistake all those guys start dancing, making moves, lunging on her, and in 2 minutes she's scared to shit and walks away. This is the bible truth about Colombo clubs. Some joints hire a few prostitutes in order to make it look alright, but whoever falls for it will be skinned alive
My advice is, tell him the truth and don't commit yourself to find that tour, because his review will include the name of the villa that sent him out with scammers.
There's no other truth here, trust me. Think at least of your own establishment's reputation.