Can you grap the shirt of the partner and hold them from going into the Non Volley Zone if you see your partner falling into the Non Volley Zone on a volley?

False - Please show me this in the IFP Rules; suppose my partner hits a volley and his hat goes off his head toward the NVZ, there is nothing in the rules that says I cannot catch the hat to prevent a fault so why not keep my partner out as well?

Until the IFP Rules state otherwise, I will disagree with this. However, if I am touching the NVZ and after volleying my partner's momentum carries him into me, it is a FAULT.