When the time came, he would just give her a piece of the gold bar as a gift and let her play with it.
This way, he would not need to worry about Elaine taking the gold bars and selling them for cash.
If this was in the past, it went without saying that Elaine definitely would have brought the gold bar out with her early in the morning tomorrow to sell it.
And before she went out, she probably would have gone into Charlie and Claire’s room to steal the other remaining nine pieces of gold bar