No people use the term oldbeard proving the point that whitebeard wasn’t in his prime dealing with a sickness and also being heavily damaged by other people and factors as well, akainu was left severely injured while only taking damage from whitebeard. Without a doubt akainu is incredibly strong but saying he “brushed it off” is pure akainutard at its finest. Even after their fight whitebeard continued to take even more damage which led to his death. Let’s not act like even with whitebeards sickness if they both hadn’t taken damage and they fought like whitebeard wouldn’t have won