Can we use this as in who wants beer?? If not can someone give an example of how it's used please,
No, if you want to ask who wants beer you would say "Hvem vil ha øl?". This sentence, while grammatically correct is pretty unnatural. "Hvem drikker øl" - "Who is drinking beer" or "Hvem dikker denne ølen" - "Who is drinking this beer" both seem more natural. I personally can't see a setting where you'd ask who is drinking the beer.
For the same reason "sugar" is not accepted for "iskrem". Or "fruit" for "eple", depending on how you look at it.
While there is alcohol in most beers, "beer" and "alcohol" are far from synonymous.