Oh my God. This is horrible. Please, please contact law enforcement to see what needs to be done so that your "Friend" will stop or be forced to stop this abusive behavior towards Animals. Please call either the SPCA, Humane Society, the Police or any other agency that may help. They will guide you on how to proceed further, and you can do it anonymously if you so choose. Please, this must be done immediately!!! If you don't know who to call, PM me, and I will find out who you need to talk to.
If your friend is willing and delighted to hurt Animals, what makes you think that they haven't thought or acted upon hurting another human being? Be careful of your own safety when you are around this person. A friend can easily become a victim.
I literally beg that you let the authorities know about this NOW, before another innocent creature is made to suffer.
PLEASE.