he is a shy guy and is very cautious in making moves since he is from a country where women are upstanding and would bash men easily. I really want to have an open talk with him regarding many things and thought maybe we have drunk night together at least both of us should be a bit high to open up. How is the idea?
If he is the shy one why don't you open up more and ask him about all the things you want to. I am shy too and I do often revert to having drinks to loosen up, but most of the time it turns into drinking together all of the time and we never actually make a good quality relationship because of that. It ends up being fun and casual drunken nights. I feel when I meet the right one we will be able to talk either way and won't get drunk together very often if at all, because it won't be necessary. I say you initiate more conversations and be patient, he will open up eventually he just needs to become more comfortable and all that helps with that is more time hanging out.
If you are drunk during this, "drunk talk" it will be "discounted" by him when he is sober and rather accepting what ever you said during this drunk talk, he will be brushing it aside and wondering what you really meant. If you really accept having a talk with him while both of you are drunk, forget it I don't want to be involved answering anymore.