Installed Pre-order content missing

We pre-ordered Fallen Order on Xbox through Amazon. We did get the Pre-Order Bonus content. And didn't install until after playing for a couple hours. When we installed, it loaded no problem, updated the items and played again. Saved the game, shut off the console. The next morning, our son played the game on the same console but a different xbox account and couldn't find any bonus content. Husband goes to play on the original xbox account and the bonus content is missing. What happened? Can we reinstall the content?