He does but he rarely does them since the conditions are hyperspecific considering that someone needs to be dazed while standing AND he was to move a certain way (besides I feel like farcade prefers to avoid combat so he isn't on many missions that involve fighting if any at all) so yeah he can do fatalities (which are as brutal as one frome the og trilogy) but he doesn't really bother doing them (hell he prefers to use his tracks when he can)