Maybe he is, maybe he isn't. But I am sure it is not for you to say.
Joh 7:24 Judge not according to the appearance, but judge righteous judgment.
You do not know Buddha, only what others say about him, so you are judging based on gossip.
Perhaps he made a deathbed confession, isn't that what you are hoping to do? ; make sure you have confessed everything to ensure you have been forgiven?
Perhaps you have used a confession like a mantra to manipulate your pagan god?
Wouldn't a true Christian love his enemy even, and rather than gloat that someone went to hell, pray for God's mercy on them?
Just sayin' All rhetorical questions. No response required.