"He died ... in a most glorious manner. He said He was going to that Country he had all His life wished to see & expressed Himself Happy, hoping for Salvation through Jesus Christ – Just before he died His Countenance became fair. His eyes Brighten'd and he burst out Singing of the things he saw in Heaven."
He was clearly on some level out of touch with reality - but isn't that what Art is really about?
We sing his poem "The Lamb" to a setting by John Tavener. There is no question to me that he Got It.
We had an older pastor who by that time had been present at the bedsides of hundreds of people who were about to die. He considered it his favorite part of his ministry. Those who were unsaved often uttered vile imprecations against God, literally and verbally shaking their fists at Him. Those who were saved often said, “He’s calling me—I must go now.”