Is it permissible for Muslims to boast about Christian graves and adorn them with flowers, considering this superior, knowing that burying a Muslim in Muslim cemeteries is not permissible?

If the boastful person shows that a Muslim's grave is better by placing flowers, then this is not permissible, as it is a wasteful expenditure of money without right and an imitation of the disbelievers. However, if the intent is that some Muslims of weak faith claim that the graves of Christians are better due to their adornment, then this is a great error and ignorance of the Muslim's standing with Allah, and the essence of His Almighty saying: "Indeed, the worst of living creatures in the sight of Allah are those who have disbelieved." Added to this are the forbidden glorification of disbelievers, the prohibited squandering of wealth, and the impermissibility of belittling a Muslim and ridiculing him.