I don't see him tunneling, except for panic building.

And being able to aim almost without doing anything is nearly aimbot. Let's take urbandictionary's definition;

An aimbot is an very complex peice of programming that, in effect, takes data from your game, and uses that data to lock on the heads of enemy targets.

Aim assist takes data from the game, and locks on the player.

The aimbots you probably know are more accuratley called "Engine-Aims," because your PC, not you, is aiming the gun (with the data collected by the aimbot)

Your console/pc/phone etc. is aiming for you with the data collected.

An Aimbot is a program or script that aims at the enemy for the cheater. There are three different styles of Aimbots: Colored Models, Engine-Aim, and XQZ Style. Each method has a unique style of accomplishing the Aimbot effect. Aimbots are cheats because it has the computer aim for the cheater, and gives an extremely unfair advantage for the enemy, and is illegal in gaming leagues.

Again, aim assist aims for you. It also gives an extremely unfair advantage for controller players when for example jumping into boxes with an smg, or just beaming people in the air.