|Goodness, don't guess I've ever heard about someone being physically "whacked" on the mouth as a form of an ADC! Most ADC's come as songs, seeing license plates or hearing songs with messages, lights flickering, seeing coins on the ground with special dates, etc. In other words, "non-physical" messages.
I've personally heard my pet puppy running down the hall; seen a spectacular "double" rainbow that was a full half-circle in the sky; seen extremely unusual clouds; had a printer go absolutely nuts trying to print, when there was nothing for it to print.
My sister had a kitty who had just passed jump up on her bed, and walk up the length of her body to her face, and meow.
My mom, as she was passing in hospice, saw her own deceased mother with my deceased young son (6 yrs. old) get out of a car. She also saw my son sitting in Jesus' lap, and Jesus waved at mom.
My aunt, as she was passing, was not told that her daughter had passed from cancer. Her other daughter was trying to hold her hand. My aunt asked that the living daughter let go of her hand, as her deceased daughter was there to take her hand and take her "home" to heaven.
I DO believe our loved ones on the Other Side can communicate with us, letting us know they are alive and well, and letting us know that they are taking care of family members who have passed. However, I am very surprised to hear about the "whack." Some folks have mentioned they have felt they are being hugged, their hair touched, etc. They've felt animals or children (deceased) jumping on the bed, etc.
I would say it IS an ADC, and, yes, messages can come from others concerning a passed loved one, in order to convey information.
Encourage your friend to read the book "Hello from Heaven" by Bill Guggenheim, and to check out this website. She will learn that ADC's are real, and I would definitely ask HER mom -- (yes, "speak aloud to her") -- to communicate with her in a non-violent way. Our loved ones can hear us talk to them, and will respect our wishes.
Some folks have been so startled by ADC's that they ask not to be communicated with anymore. I would imagine that is very rare, though. Most folks here are thrilled, though perhaps a little nervous, to get messages from the Other Side! :)