no. 1443 for the year 2004 which includes the following:
There is a young religious man in our village who leads prayers at the mosque. He enjoys a good reputation except that he works in the field of tourism and procures beverages, alcoholic drinks and the like for bars. Some people have objected to his imamate , but there is no one else in our village more qualified for this task. Is it permissible for such a person to lead the prayers in the our village?
 

The principle is that if a person's prayers are valid for himself, then they are likewise valid for others if he serves as their imam. For this reason, Hanafi and Shafi'i scholars have maintained the validity of the imamate of an immoral person due to the numerous hadiths attesting to the permissibility of praying behind the righteous as well as the immoral. Even though these hadiths are classified as weak, their multiple chains of transmission strengthen one another.

Some Companions reported that they used to pray behind unrighteous imams. In spite of this, it is disliked to take an immoral person as an imam even if he possesses qualifying characteristics that preponderate him for this task. This applies to a person who is not the mosque imam; otherwise he takes precedence over another.

The ruling
If the person is a mosque imam, then it is impermissible arrogate his prerogative to the imamate since he supersedes any other person. If not, then someone else who recites the Qur`an and prays well takes precedence over keeping an immoral person as an imam. In the absence of such a person, it is obligatory to give him precedence over another; prayers performed behind him are valid if he observes all of its conditions, integrals and obligatory features.
Allah the Almighty knows best.