Im sorry to hear that about your dad, it must have been horrible
as to the why the heck they called, I may have an idea. See I am a cosmetologist, and theres this client of my co-workers (shes one of my fav in the shop) shes a funeral home director, and she tells us a lot of stuff that happens there, some very cool stories.
but anyway, usualy funeral homes do a yearly vidual (I know thats not spelled right, but I cant find the right spelling...

) for all the people that had died that year. They invite all the familys back and do a candlelight thing, sometimes there is food. I bet you that is what it was. Your dad might had died right after they had there yearly thing or something.
I bet you thats what it was. Im sorry to hear they did such a horrible job. Its a hard job to do, and I dont envy them what they do. But it still gives them no right to do what they did to you. Im very sorry.