Thorin, in his horrible sickness, who “will not part with a single coin” of the treasure, gives Bilbo a piece of it worth more than all of his homeland. This is so important. Thorin was level 100 sick at this point, ready to go to war, but somewhere in his mind he was still worried about Bilbo. He still cared about him, and willingly gave him such a priceless piece of the treasure he was so obsessed with. I think that says enough on its own.