A brother had a five year affair. His wife didn't know about the affair. He says he has repented. Can he work in the worship service and be one of the spiritual leaders? What does he need to do?
"If we confess our sins, He is faithful and just to forgive us our sins and to cleanse us from all unrighteousness" (I John 1:9).
"Take heed to yourselves. If your brother sins against you, rebuke him; and if he repents, forgive him. And if he sins against you seven times in a day, and seven times in a day returns to you, saying, 'I repent,' you shall forgive him" (Luke 17:3-4).
How long the brother sinned does not matter. Who knew of his sins does not matter. What matters is that he has had a change of heart and a change of behavior. If he has gone to God to ask for forgiveness, then it can't be held against him.
You should put him to work. It would be advisable not to put him in a position where he might be tempted to sin again, since he has already shown a weakness in that area, but where he can be of use that is safe for him, then put him to use.