According to Wizard101 wiki, deer night doesn't heal. Yes it does. I have personaly seen it use spritely and unicorn. He was ancient.
Any talents from any other pets can be hatched into a current pet so what you have seen is someone who has worked very hard and hatched with other pets that could or have that talent for that Deer Knight to have those abilities.
So Wiki is still correct on the first generation talents of the Deer Knight pet.