Try to remember how different all people are from each other. We have always been a little more concerned about our daughters development than that of our three boys because she just seems to do things at a later age, whenever we get to worrying a little much, we try comparing ourselves to OUR siblings, since we are so different how can we expect our kids to be the same (as each other, and others in their age group) It helps us, anyway :)
I also have a friend whose daughter only said a few select words until the week of her third birthday, when she started speaking in full sentences!
Have you considered learning ASL with him? I still use it with my older kids, it sometimes seems to be easier for them to communicate with their hands when they are upset. Of course, my youngest refused to communicate in any way except whining until he was almost two-it was so frustrating to me because I had been able to understand the older ones so much sooner.
I am a student, and just completed Human Growth and Development (GREAT class when you have kids) The book said that many children don't communicate much verbally until around the 2 1/2, which surprised me since most of the children I have known in my life spoke much sooner. Maybe your Doc just wanted to make a note of it, as something to be sure and keep an eye on.
I tend to take a wait and see approach on most develomental things with my kids, and so far everything has been fine. I believe that as moms we know when something is really wrong with one of our kids, and if you feel something is wrong then take action, but since you aren't all that concerned I'd say wait a while and see what happens.
Good luck!
~J.