Translation:He usually wants to sleep eight hours.
I'm guessing because it's infinitive form. brukar is a verb meaning to be used to/to tend to
so, He tends (brukar) to want (vilja) to sleep (sova) eight hours.
out of curiosity, and I'm sure that Swedish has another word for it, but can you not add 'tends' for 'brukar'. It's a good word to use in the present tense for it. One of the suggested answers is wrong in English, that's why I ask. (He uses to want to sleep 8 hours).
I thought that "He usually wants to sleep for eight hours" would be a good translation for this swedish sentence. Am I wrong?
I personally think this sentence sounds a bit more natural with a preposition, in both languages. There might be a tiny difference though (8h in total vs in one stretch) but I would phrase it differently if I wanted to distinguish that, but opinions might differ. The preposition in Swedish would be "i".
He usually likes to sleep eight hours? Why is that not accepted? Vilja can mean like to, as in 'Jag skulle vilja beställa en pizza tack'. No?
It could mean "would like" as in your example yes, but even in your example, that's just a more polite way of saying want. It doesn't mean like as in enjoy, so you wouldn't use the like in "would like" (when it means want) in the infinitive.
This sounds strange to me—I would say "for eight hours" (I'm not sure if that's already accepted as this was a word-tapping exercise for me).
Is it acceptable to say "han vilja sova brukar åtta timmar"? Why in this case you don't apply the grammars rule of the verb goes in second place of the phrase?
"Brukar" isn't an adverb like in English, it's a modal verb like "Kan/Ska/etc"