Is it permissible to pray for money on behalf of a mosque's imam who is absent from the obligatory prayers?

Whoever is appointed as an Imam for a mosque must fully commit to leading prayers and not be absent except out of necessity or need. Otherwise, he is sinful, and the money he receives is unlawful (haram (definition)). His appointing another Imam to lead in his place does not excuse him, except in cases of valid excuse. In such a case, there is no harm in you leading the people in prayer on his behalf, without remuneration.