Well, I know my friend Q for a long time now, but for stupid reasons, we didn't see each other for several years. But throughout this years, he didn't stop sending me messages (emails, papers in mailbox, anonymous phone calls... ), I recognize it was from him (he didn't show clearly it was from him, but there always were references of him), he also asked some other friends of me to tell me things so I could understand that he wanted I go to him.
So, I left my country to his country (USA) to see him, but now, I'm here for nearly 2 months (and of course he knows it) and every night and day he sends me messages saying he loves me a lot (Ex : There was a passing car in the street, and a boy in the back sit of the car, called me "you", he Said, I made a sign pointing my finger to me (Me?) and he said "yes, you. I love you.". I know that it was my friend Q who ask this boy to tell me that, I only know him here, and examples like this, I have lots. He put the cameras in my hotel room. He spy what I'm doing on my computer... )
But he always refuse to see me.
He never tells me things face to face, he asks other people to tell me or to make me understand.(Is this normal?)
I think he is really sick and he needs help but he is also really smart and he will persuade anybody that he is not sick.
Well, I don't know what to do, but I think if I do nothing the situation will stay unchanged.
I really think he has to go to the hospital or someone needs to help him (I can't), he can stop contradicting himself and I know what he truly thinks about certain things.

He put the cameras in my hotel room. He spy what I'm doing on my computer.
Please explain these.

In the US, only medical doctors can have a person committed.

I can see how the behaviors you describe would be frustrating and aggravating to you. However, they fall far short of posing a danger to your friend or any other and that is the standard for involuntary commitment in the US.

The conduct you have described seems to be better described as childish or immature as opposed to pathological. Doubt seriously that a hospital could be of much assistance.

Since there is no direct communication between the two of you it sounds as though the situation is beyond your control as well.

Thanks everybody for your answers.

Explanations :
Well, he puts cameras in my room : I write a question on a paper in my room and I get an answer either with the sound of an horn or someone says something behind my door or I get what I wanted (Ex: There is an annoying noise out (somebody mows the grass or something like this), I write "I'm thinking of you, if you could stop that noise it will be nice", less than 3 minutes later, the noise stops. Ex 2 : I was a little bit ill one month ago, so I was laying down my bed in the afternoon, then a horn at 6:03 pm (which mean 6(sick), 3 (you)), I writed "yes, i've pain ...", after a horn at 6:14 pm (which means "sick one for"), I writed "i have pain for 3 days", after a horm at 6:38 (which means "sick you hate"), and after a horm at 6:43 (which means "sick for three").
He spy what I'm doing on my computer : I was looking at webpages about how to drive an american car, then I received a phone call from the receptionist asking : "Would you like to have a car, i will bring you one...".

I'm not sure I understand this. Why are you writing messages to him in your hotel room? Did you agree to him putting a camera in your room or do you just think he did? Do you mean a webcam? If someone is mowing the grass, how do you think he makes it stop?

These horns. Is it some kind of code you two have worked out, or is it that you have worked out what the horns mean for yourself?

Are you on your own since you moved to the US? Do you have any friends you can talk to about all this?