I guess it's a sentence from the book Harry Potter. And the original English version of the sentence is "The Dursleys got into bed. Mrs. Dursley fell asleep quickly but Mr. Dursley lay awake, turning it all over in his mind
”怎么也“ is often used to emphasize something following. e.g. 怎么也找不到 mean "can't find it at all", and "怎么也醒不来” means can't wake up at all.
Hope this helps a bit.