Hmmm
It's a brand new bike yes? Is anything funky up front, a bent front rotor or loose steering head? I assume the basics were checked first?? I can't imagine why it would shake so much during braking only? or just decel in general? I can offer no real suspension settings, the book says so much, I went that route about 10 clicks backs from full on compression and so forth. Basically I went with what the KTM book considers the "hard" setting. I have no shake that I consider worth noting.......... So that's why I ask did he get a bent front rotor or is something loose up front??
Please let me know what you find for future reference, sorry I couldnt be of more help :think