All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
The prayer behind the said Imaam is valid, and his bad conduct, toughness and not marrying, all these (if they are true) do not render the prayer behind him void. He might have a personal excuse for not marrying that no one knows, so one should not be harsh with him for this reason.
Indeed Allaah Says to His Prophet (what means): {And if you had been rude [in speech] and harsh in heart, they would have disbanded from about you. So pardon them and ask forgiveness for them and consult them in the matter.}[Quran 3:159] Thus, Allaah warned His Prophet
against being harsh in speech, and ordered him
to pardon the believers, seek the forgiveness of Allaah for them and consult them.
Toughness and harshness are not one of the characteristics of the people who call others to Allaah and the scholars. Therefore, if this is truly his character, then those who know him should advise him so that he would be soft in his behaviour with people.
One should consider people’s circumstances when establishing the prayer, like cooling water in very hot weather, and the other things which you mentioned. Softness and gentleness beautify things and when they lack in something, they make it boring.
On the other hand, you should not magnify things beyond their scope. If the Imaam is right in some of his behaviour like preventing the mosque from being used as a hotel, or preventing people from being too extravagant in using water and electricity while there is no income for the mosque for paying the bills, then the congregation should help him in taking care of the mosque. All of you should bear in mind the Saying of Allaah (which means): {Help you one another in virtue, righteousness and piety but do not help one another in sin and transgression.}[Quran 5:2]
Finally, you should beware of division and dissension as this is evil, and remember that you are all brothers in Islam and one nation.
Allaah Knows best.