Is the sentence ok?

What do you want your friends to be treated with?

This sentence is rather peculiar. One can be treated with contempt, or with respect--but basically, this is an uncommon locution syntactically. You might consider: How do you want your friends to be treated?

No, sorry, the meaning isn't clear.
Do you mean....
What do you want your friends to be treated with? (eg antibiotics)
How do you want your friends to be treated? (eg with respect)
How do you want your friends to treat you? (also with respect)

Thank you Set.

Can we drop "with"? I want one of the word cancelled without changing the meaning of the sentence.

You can drop "with" if you change "what" to "how" at the beginning of the sentence, as in the example i provided. The sentence is odd, but not grammatically incorrect as you wrote it. However, if you write: What do you want your friends be treated, and even if you change it to: . . . to be treated."--it will not be grammatically correct.

Okay. What I intend to convey is:

You invite your friends to come to your house. You want to treat (serve?) them with apples, pineapples and watermelon etc. Last night, you elder brother has asked you in telephone:" What do you want your friends to be served? Apples? Watermelon? Peaches? I will buy them and bring back for you when I come home tomorrow morning."

Okay. Is the sentence "What do you want your friends to be served" okay?

Oops! It was far from what I wanted to say.
Of course it is my fault, not yours.
Thank you for replying.

Yes, and not only is it correct, it is how a native English speaker would be more likely to say it. Your sentence, What do you want your friends be treated with? can be fixed by adding "to" as i have already indicated, and, in context, it is not only not be incorrect, but it makes sense.

However, What do you want your friends to be served? is much more likely to be how a native English speaker would ask the question.

Cool.

Thank you Setanta.