I suspect that the older brother was jealous of his younger brother, and even more angry that he had repented in humility.
It reminds me of the little boy who was commanded by his father to sit down. The response of the child was "I will sit down, but I am standing up on the inside."
How many people pretend to love the Bible but act contemptuous toward those who quote scripture to correct their error.
Narcissists hate those they perceive as less perfect than themselves, but show even greater contempt when these "lesser" people confess and turn from their sin.
Narcissists love to see people sin, it makes them feel superior. A truly humble person is saddened and even angered at the sin in the lives of those they love, but have a greater degree of joy when they repent, confess and return to obedience.
Lacking empathy and kindness motivates the narcissist to choose to see others in a negative light, when they cannot do that legitimately they will make something up.
The greatest degree of prodigy is to pretend to obey on the outside while seething with contempt and anger on the inside.
Outward obedience is not the measure of a godly life, pretenders can do this, it is the responses that come out when we are faced with reality about our own hearts.
Matthew 15:19 "…18 But the things that come out of the mouth come from the heart, and these things defile a man. 19 For out of the heart come evil thoughts, murder, adultery, sexual immorality, theft, FALSE TESTIMONY, and slander. "
It struck me as I read the phrase, " false testimony." Many people have a verbal and even physical testimony that appears to be real, until they are challenged to a greater holiness, then the real them emerges to defend themselves.
Psalm 51:17
"The sacrifices of God are a broken spirit; a broken and contrite heart, O God, you will not despise."