Eric
I married into a chinese family and in the early days of my marriage (30 years ago now),when someone in the family passed on there was a mourning period of 100 days during which time we had to observe a few protocols related to respect and mourning. One of those was not being able to actively socialise - maybe this is why your friend's mother was not keen for you to visit - out of respect for your grandmother rather than superstition that something bad might happen to her.
As a QiGong practitioner I don't think qi gong involves either religion or superstition - and certainly I don't think there's any bad Qi - just too much or too little that may be in the right or wrong places. That being said, and as IAM2 says, we have the power to move the Qi once we know how.
with love
Jetay
