Before providing you the sample memo, we need to understand few things. First one is about accommodation. Is it self-independent accommodation or dormitory. Either way, the staff must have consumed the alcohol during their off-duty hours. If this were the case, then why company should bother about what happens in the personal life of the staff?
Yes, I understand that UAE is not a democratic country even then also some personal freedom or some rights of the citizen are always preserved.
Going further, did your company take undertaking from the employees on prohibition of consumption of alcohol in the staff accommodation?
Please provide complete information. Your 14-word post is too short to give opinions of any kind. Lastly, I recommend you writing memo on your own and uploading on this forum. Some senior like me will correct it.