As to their son's belongings, she could retrieve them for him--they are their son's belongings, so he would have a right to them, and with his permission or authority, she could retrieve them.But as an ex-wife, she had no right to anything owned by your son which she did not already own (e.g. it was jointly owned by the two of them), or was not willed to her (and even there, she procedurally jumped the gun, so to speak, in doing this, but if at the end of the day, she would have inherited the item[s], there was no harm done). Anything solely owned by him (e.g. not jointly owned with the ex-wife) and not left to her in a will is something which she had no legal right to take and which, if she did, she stole. Your son's estate, by it's executor (if there was a will) or court-appointed adminstrator or personal representative (if no will) could sue her for the return of those items, such as the gun, or their monetary value.