What did Andre need the money for?
He's already a wealthy resident of Aspen.
He might be rich, but not crazy rich like most of the other people of Aspen.
Or he had a personal vendetta against Mary's family and this was his way of getting over on them.
Or he was super rich, but was racking up some bad debts, and did something desperate for quick cash.
With wealth often comes greed.
Besides, maybe he'd become wealthy due to his criminal activities.