i would not be concerned about your son "clinging" (forgive the pun) to a cherished transitional object such as this stuffed bear. my daughter slept with the torn and tattered remains of her baby blanket well into high school. she ultimately gave it up spontaneously before college -- though you can bet it was not discarded just put away. if all else is good put this issue far out of your mind.
my 14-year-old son still uses his "security blanket" (a very ragged stuffed animal). is that normal?