I went to a Griever's meeting yesterday and spoke of how my late wife comes around to visit me (and others). Some of the Grievers have the same experiences with lost loved ones and some don't. Those who aren't willing to believe that the "dead" are still alive are quite skeptical and those who have "visitations" totally enjoy it.
I can explain how my late wife comes around but could never prove it so all I can offer someone is what I currently know and feel. If someone wants to learn more about the Afterlife and visitations, I'd recommend you google: James Van Praagh or the Afterlife and read up on the subject. IMO, those on the other side come to us a lot BUT we reject or push them away with our fears and skepticism. They just want to let us know that they are still here and that they love and respect us so it hurts them to be ignored and dishonored by us.
It can improve one's grief work to know or even accept that our loved (or hated) ones are right here, listening to us and willing to make amends or give us a loving hug whenever we are ready.