What are a blackjack dealer's options?
Blackjack dealers have no options for the in-game decisions of whether to hit or stay; they follow a strict algorithm that will depend on the casino. The dealer waits until the players have exercised all their options, then the dealer reveals his hidden card and hits until he has at least 17 (most common).

The only variation I'm familiar with is a rule where the dealer will hit a soft 17 (any 17 with an Ace taking the value 11--denoted "H17" for Hit 17, as opposed to "S17" for Stand 17), but this is not the dealer's choice, it will be determined by the casino. According to Wikipedia, this rule will generally be printed on the table if it is being used, and it hurts players. Wikipedia phrases it the other direction: going from H17 to S17. 'Substituting an "H17" rule with an "S17" rule in a game benefits the player, decreasing the house edge by about 0.2%'

See @NiceVerAz's answer below for a nice explanation of "meta-game" options that the dealer does control.