Should we say happy Christmas to Christians??????????

We can console people of scriptures if they get shock , we can congratulate them on social celebrations like marriage ceremony or passing an examination .We can do business with them provided that transaction is halal .We can eat with them provided that food is halal .Muslim men can marry their chaste women but we cannot cannot copy them because it has been prohibited by Rasool salal laho aliehi wasalam.We cannot greet them on their religious ceremonies because by this act we are endorsing their wrong theology and impure beliefs.So we should not wish Christmas to them .