If you feel compelled by the Holy Spirit to share the Gospel with him on his death bed, Then DO IT! My FIL accepted the Lord on his deathbed. He couldn;t even talk but as I shared Jesus with him a stillness and peace came over him in the bed and he became very peaceful and the Lord gave me assurance that he heard me and accepted the Lord. God can reach someone even when you think they can't hear or understand you. I was priviledged to be able to witness this so I know its never too late to share the gospel with someone.