Swollen Legs And Numbness

Hi, this is in regards to my 14-year-old brother. For the past couple years, he has had an ongoing problem with something I cannot find the answer for.
Symptoms:

By the way he describes it, and what we have seen on occasion, after standing for more than a few minutes, his legs and feet begin to turn red, starting with the feet and slowly moving up. This is accompanied by a tingling sensation all over his legs/feet. This has gone on for a while, but the symptoms have gotten a little worse just in the past few weeks......

Now he says that dark blue (almost purple) splotches a little smaller than the size of a baseball start appearing on his legs, and there is a small but sharp pain in the back of his upper thigh (unfortunately, I haven't seen these yet).

The sensation (while standing) has now started to move up through the Right Quadrants of his abdomen to his right arm. Once it gets to his arm, by his account, the arm immediately becomes numb (not to the point of dead, but the same feeling as if he had slept on it). I've done some research, but I'm kind of at a loss. We've taken him to a pediatric cardiologist, and nothing was found on the echo. His diagnosis was that he was "A weird kid," and that he would probably grow out of it. I'm just searching for a second opinion.

Thanks,
Martin