I have worked in Qatar many times and have also worked for Halul.
There Project Manager Andy is a good lad so you will be ok there.
Qatar as a place has grown in the last 5 years, Not sure if it is true about not getting a beer during Ramadan, As i have lived in Dubai for the last 5 years, And even Abu Dhabi where up till a year ago was dry through Ramadan, Now like Dubai you can get a beer after 7 o clock.
Enjoy your trip ther is a british club just outside the city beside the new sports arena they built for the asiam games last year think its called Garlands cant remember.
There are plenty bars to go to and girls if thats what you are looking for.
If you are working for Halul you may be stuck out in Ras Laffan, About an hour from Qatar centre and nothing to do there as its the main terminal for the LPG.