Is AUTHOR wrong in the post ? POST : Throwaway for reasons.

8 months ago my husband passed away. He had an adult son from a previous marriage and the two of them weren't very close. I don't think they hated each other or anything like that. Honestly, I think the divorce had more to do with it. Because of reasons I won't go into here, his ex-wife basically had sole custody of their son and the two of them never had a chance to fix that relationship. 

Anyway, my husband held some animosity about the whole affair because he felt like his son sided against him in the divorce. Right before he passed he made me promise not to give his relatives any of his possessions (he had a bad relationship with his family and he owned some family heirlooms) and I asked him "what about \[son's name\]" and he paused and he said "he doesn't get anything either". Honestly, I was shocked, but I was pretty much grieving at this point so I didn't question it. 

Well, about a month ago his son reached out to me over email asking if he could have a couple of his father's items. He said he's been regretting that they never repaired their relationship and that he never got to say a proper goodbye. The items he asked about were small things like a gold lighter he remembers (I still have it) and a blue button up shirt (I don't know which one specifically, but I still have all of his old clothes). I responded and told him that unfortunately it would go against his father's wishes to give him anything and he replied very politely "I'm sorry to hear that. Thanks for responding." and that was it. 

About a week later his mother sends me an email calling me names and a bitch for not giving her son the things he asked for and that I'm basically preventing him from moving on. I didn't respond and I blocked her email and I haven't heard anything since. 

I've been feeling sick ever since this happened. I'm still trying to move on from his passing and I'm not trying to stop him from moving on, I'm just trying to honor my deceased husbands wishes, but I feel like I've done the wrong thing and I don't know how to handle this. 

Was she right? Am I in the wrong?