It is a hard spot to be in...and I'm currently in it too with my identical boys. One is the showy, tell everyone the answer and make it known he's "smart" kinda 5 year old, the other is the shy, reserved, hide if someone is paying attention to me kinda 5 year old who can do the same amount of work or more than his twin but the teachers never see it or testers. (He had hidden that he could read from his teacher until last month, until I told the teacher at the teacher conference, just by simply not ever saying anything in reading time)
I would agree with the others, I would look for private testing for your shy one (if the school will possibly accept it). A tester that is experienced with gifted children of all types will be able to work from the right angles to allow the child to open up. The GDC does say what flower said about how siblings often being within 5 (ish) points. They recommended I watch my twins very carefully for signs after testing my oldest (PG) son.
It's so hard when the options differ between the two, especially with identicals because it just doesn't work to say " well let him go into this, or advance in this...but leave the other behind..." I'm not willing to do anything like that as emotionally it affects my twins both so much and my shy one needs to know his brother is near and being treated the same, especially in these younger ages so I don't envy your position right now. Good lucK!
