。
Even if he fails, what does it matter?
Literal
Even-if-たとえ he [subject-が] fails, what-matters [question-か].
たとえ~ても ('even if X') is a concessive construction, paired here with the rhetorical かなうものか ('how could it matter, who cares'). かなう ('to be a match for, equal, accomplish') with the rhetorical か ending produces a dismissive 'who cares, it doesn't matter.' Characteristically casual and flippant.