One thing that JP Morgan did wrong is that he decided to do that because one of his company's was related to the War business. This business included selling defective rifles to the union soldiers. Which was illegal, but he was investigated for this, but he was never charged since it was said that he was ignorant of the poor quality of the guns.
He helped with the Financial Panic, as previously stated. But one thing he did to truly help with the crisis is "Morgan organized European lenders to purchase $65 million worth of government bonds with gold to replenish the money supply." (captionsync.com) This helped bring money back into the economic system of the U.S.
Morgan died on March 31, 1913, in Rome at the age of 75. Possibly due to Tobacco use, he smoked so much that the company's cigars he was smoking was renamed "Hercules's Clubs' “, and has a skin disease that gave him a bulbous purple nose, and a disinclination. But, actually dies because he could not eat, and had symptoms of delirium.
After dying he gave his money to his son at the time (John Pierpoint Morgan Jr.) $80 million, which is roughly $2.2 billion if you account for inflation to current times (2021). And, while he was still alive he collected fine art to later donate to the Metropolitan Museum of Art.