Re-think the purchase. The price may be low due to major structural issues that the seller knows about and can't afford to fix. A qualified home inspector in the area (your hire, not the agent's) can tell you whether or not this type of a solution is common in the area for a cantilevered deck.

I think you will have to tear down the deck and rebuild. if the foundations are ok, not leaning, you can use those again. the way the wood is attached to the concrete foundations tells me that was not the original deck. I would proceed with caution or at least adjust the price to account for a new deck