Is it a sin?!?!, Cathay,

Well, if you're referring to it in a Judeo-Christian sense, then I guess everything having to do with extramarital or premarital sex is "a sin." If you are asking on this board, then everyone will probably tell you that it's not, since by definition we're all "sinners" here.

Having said that, I find it interesting that you bring up Isaac Newton. We actually don't know very much about his love life at all - maybe Isaac was a closeted gay person? Or maybe he was transgendered? Or maybe Isaac had some secret love stashed away somewhere?

Aaah, but I digress. I don't know if a provider will "teach him how sex works" - that will depend on who your brother ends up with. Also, let's hope he understands that a provider will never be "a lover" to him, but a paid sex partner by the hour. My advice would be to show him TER on the web but leave it at that. If he doesn't act upon it, then it's really his life and his problem.

Tycho Brahe apparently was much more of a joyous rockstar of this time,
The Love Goddess

It was once a tradition for an older male family member...  often an uncle... to take the gentleman to a lady of the evening in order to teach him the ropes.  Yes, even in the USA.  

Not all providers would be good with virgins...  though experienced MILFs can be very good at this...  they may have the patience to guide & teach.  

IF your brother has devoluped some fear of intamacy, because of his inexperience...  this might be just what he needs.  

I do not feel that paid sex will ever replace the emotional bond between 2 lovers...  but if one does not have an available lover, it can be a great comfort.  Also keeps the pipes from becoming clogged.

BTW, any sex student should not just rely on paid partners but also read the great deal of material available in order to be a better lover.  As an older man, I have found great pleasure in pleasing my partner as much or more than myself...  

Virginity is way over rated.
skb

Your description of your brother, right down to his career choice, is the classic description of a male with Asperger's Syndrome. I'm not saying that he suffers from that...just an observation.

Sir Isaac Newton is remembered for his accomplishments centuries after his death.   Virtually all of his contemporaries were fogotten by 1700.  Sir Isaac has his place with Aristotle, Leonardo, Galileo, and Einstein as amongst the greatest minds in history...

If he wants your help getting laid, be a good sister.  If he does not, be a good sister...be subtle, but never force things!

Perhaps my experience will be helpful to your brother.  Because of several factors, including growing up in a loving but conservative family, and some shyness on my part, I was a virgin until quite late.  As a virgin at age 23 years, I decided it was high time to be with an escort.  These were the ancient days before the web and resources such as TER and Eros.  I called an agency that was advertising in the classifieds, and had an escort a couple of years younger than me make an outcall to a hotel room I had reserved.  Although she was very attractive, it was clear during our hour together that she was only providing a service.  From porn and other sources, I was reasonably familiar with female anatomy and the mechanics of sex.  Although my time with her was not the most passionate or physically pleasurable, the moment I pushed my cock into her pussy was of enormous psychological pleasure that I remember with fondness to this day.  I thought to myself at that instant, "That's it.  I'm not a virgin anymore."  I thrusted in and out of her somewhat mechanically, but soon came.  She left not even realizing that she had taken my virginity.  After an encounter with a second escort some time later, I had developed enough confidence that I could start having sex with other women, both escorts and others, and truly began enjoying myself.  In fact, the roles were reversed when I took the virginity of a wonderful young woman whom I had known for a couple of years and who was 19 years old when I finally made love to her.  Even after marrying, I have continued to have sex with escorts occasionally.  I regret not enjoying years of relatively carefree, promiscuous sex as most of us did when teenagers.  Nevertheless, I am truly grateful to all the escorts with whom I have been, who have allowed me to have a very fulfilling sex life with many partners from around the world.

I do not know whether your brother will have the same experience as me.  However, since he has expressed some interest, you should definitely introduce him to the resources available on the web (which I never had), and teach him the basics of escort etiquette.  He can then decide on his own path.  Good luck to your brother.  I hope this helps.