Clothes for skinny kid - NYC

[Marshmallow]

I recently bought my son some business clothing for on campus recruiting for internships in accounting and finance. My son is a normal height but very skinny. I had some questions and would appreciate any comments or answers to my questions.

When I went to buy my son a suit I had a very hard time finding a suit in his size - 36R. I went to many of the department stores in the NYC area (Saks, Neiman Marcus, Bloomingdales, Lord & Taylor) and they had no suits in 36R. I took my son to Brooks Brothers to buy the Fitzgerald during their summer sale but the 36R was a bit tight. The tailor said that he could let it out, but I was afraid to buy a suit that was too small. Is it a good idea to buy a suit that is tight, hoping that it will fit after being let out? I finally found him a grey pinstripe Calvin Klein suit at a store called Rothmans and a navy Hugo Boss at Nordstrom (during their Anniversary sale). Both suits were perfect fits. If my son needs a suit in the future, where can I get him one? I am looking for a Brooks Brothers level of quality and my price range is about $400 to $700. I am afraid to do M2M because I dont know where to go and I dont know how to design a suit.

My son will need pants and shirts for his internship, which will probably be business casual. I bought my son 2 pairs of Hugo Boss pants (size 30) during Nordstrom's Anniversary sale. They fit him well. My son will want flat front pants. Any suggestions on where to get pants? The tailor asked us what kind of break to make on the pants. We did a full break but the pants puddle a bit on the bottom. Is this the proper break to do?

For shirts I took my son to Brooks Brothers for their slim cut shirts. The salesman said that since my son is skinny we should do a point collar. I'm not sure this is right, since a point collar only accentuates his thin face. Is the collar type based on the shape of his face? I bought 2 point collar shirts and one Ainsley collar (spread) shirt. I like the way the Ainsley collar dissappears into the lapels of the suit. What type of collar should I buy in the future? Is there any other place to buy slim cut shirts in NYC?

Thank you for any suggestions.