Not allowed to lead taraweeh due to where you work

My son is a hafezul Quraan and he has lead the Taraweeh salaat at a certain masjid.The trustees one day accused him of shaving his beared.However,his beared naturally does not grow long.When this was realised by them,they then said that since he works for standard bank he gets paid in interest money and therefore they cannot read their Taraweeh salaat behind him.My son is in the property division of standard bank.
Do they have a case against the son?