First of all, it’s mislabled. It says he “destroys catholicism”, but his debate is with Dr. Lane Craig over whether or not there can beobjective moral values without God…regardless of “catholicism”. And Dr. Craig is not Catholic to begin with. If your friend really wants a response, he should look beyong the 11 minute retort by Sam Harris and find the whole debate where I am willing to bet that Dr. Craig makes a very strong case that Mr. Harris probably* was unable to refute…thus the fact that all Harris posted was his 11 minute portion.
(*my presumption)