He was laughing (ha ha ) was mentioned there in the chapter.
Imagine saying he did nothing when oda literally spoon fed to you all by saying it weakened Garp.
He literally pierced Garp abdomen and was huge factor why he went down....
He accompanied the goal
And, don't bring sanji into this - someone who struggled to beat queen shouldn't be brought up in argument of YC1
Of course it weakened garp. He got stabbed through his organs and skin. He's hurt for sure.
It was still a sneak attack. Doesn't represent power levels. Squard stabbed whitebeard. So don't get a big head.
Whether or not he weakened garp... doesn't matter. Squard is fodder to whitebeard and yet he still weakened him badly...
Garp then turns and one shots shiryu. Absolutely demolishes him AFTER figuring out his df ability and detecting him mid sneak attack
Shiryu was detected during his sneak attack. And then got one shotted. He was mauled by garp who was handling multiple fighters at once and already weakened through aokiji.
He's fodder to garp. In a 1v1 shiryu is literally low diffed.
Sanji would perform better. He's undeniably stronger than shiryu. Shiryu has 0 feats to suggest he's even a quarter of sanjis strength.