Another RC apologist commented on DA’s blog (when he declined exegeting Romans 4:6-8):
I can answer White’s question viz. who is the blessed man very easily. He is the justified believer who God reckons (logizomai) righteous because He has made him righteous in justification. That’s what the etymology of dikaiow would have us believe anyway.
Great: so, if this person commits a mortal sin, to whom is it imputed? Him, or someone else?
If this person commits a venial sin, to whom is it imputed? Him, or someone else?
If either sin is imputed to him, how is he the blessed man to whom the Lord will not impute sin?