Blackjack Advice for this BJish game. (dealer 2 down cards, 3 up cards)

Some guys I know play some card games slightly off. One of them is a variant on Blackjack where the dealer, instead of getting 1 up card as his first card instead gets 2 down cards and 3 upcards. After the players finish, the dealer reveals the downcards as his starting hand and then plays the game, using the upcards in the order they were dealt if necessary. Dealer hits on S17 and H16 and takes all doubles and splits if he gets BJ. If he uses all 3 upcards and still hasn't bust he wins against all non-BJ hands. What's a good strategy for this game?

Source.