Are felons covered under Housing Discrimantion Laws ?

Landlords have every right to refuse tenancy to a felon, since felons are not a protected class under discrimination law. That he is 'very Christian' is quite irrelevant. (HINT -- "Very Christian" types are not always good tenants). Your friend simply has not searched sufficiently for a landlord who will accept his felony conviction from the past. It sounds to me like your friend is making excuses.