ADAM SANDLER’S comedies can usually be distinguished — if that’s the right word — by setups so improbable that they border on the ridiculous, from the re-education of a man forced to complete grades 1 through 12 (“Billy Madison”) to the sham gay marriage of two heterosexual firefighters (“I Now Pronounce You Chuck & Larry”). Yet his latest movie places him in what may be his most improbable scenario to date.