What happens to Silver during the voyage home?

He escapes the Hispaniola.

They head for the nearest port, in South America, so that they can hire more hands for the voyage home. When they land, they are given a warm greeting and the doctor, squire and Jim spend all night on land. When they return to the ship, Ben Gunn informs them that Silver has escaped, taking with him three or four hundred guineas of the treasure. Believing that Silver might have killed him, Gunn did not hamper his escape. The other are relieved that he is gone

They head for the nearest port in South America, to hire some sailors. Dr. Livesey, Squire Trelawney and Jim went out of the 'Hispaniola' on one of the boat and spent the whole night there. When they came back on the 'Hispaniola' Ben Gunn told them that Silver ran away with sack of coins. Dr. Livesey said that he wasn't expectibg to get rid of him so cheaply, and they all chuckled about it.