A similar entry appears in the Wheel of Time Companion confirming the information available in the main story arc.
Author: Toral Delvar
Perwyn Belman is the son of an Andoran Darkfriend that Padan Fain stays with when in hiding. He calls Fain Mordeth and brings him news that a Gray Man tried to kill Rand. Fain reacts badly to this, losing his temper and hurting Perwyn by simply touching him, causing him to tremble and start gibbering. Fain believes that Perwyn will survive what he did to him, but doesn't really care.
His mother is Nan Belman.
(Reference: Lord of Chaos, Chapter 28)