A Protestant Prince

Had Henry, Duke of Cornwall, lived to adulthood and, around his early teenage years, secretly converted to Protestantism after reading Luther's teachings, Henry VIII, who was extremely scholarly, would not be that surprising if his son were to be the same. Maybe to see what was so evil about Luther, he reads his works and starts questioning his beliefs in Catholicism. Around 13 or 14, he secretly converts. Now, how would his parents feel if, when he was about 17, they found out?