Everyone you suspect of botting, cheating, hacking, you need to report to our support. They have the necessary tools and will investigate every incoming report.
Now please do not get me wrong, but the video you linked, looks pretty much just like how I look after some hours of farming

You get used to the mob spawns, your eyes are starting to blur, your hand-mouse coordination starts to become abrupt and I even occasionally run into a fence and totally fail to realize it until a couple seconds. Meanwhile - since farming tends to be a boring grind - I listen to music or watch a video or chat with family and so I am mildly distracted. I get up for a few minutes whenever I feel like it, to go for a smoke, to stretch, do check on laundry or start cooking dinner.
Granted, someone following me around like you did there would most likely get me to ask if I can help my follower in any way, but sometimes I am not even social enough for that. Sometimes I wait until the other player says something and simply ignore them.
Now I can not see from the video if you tried to chat with him or not.
But just from that video, all I see is a farming player, there is not enough proof for a botter. So further research of said player is necessary, some monitoring over random periods of time. Only our support can do that.
Just by that video I would not ban the player, but I am not a supporter.
So my guess is there is still some research going on or no proof of botting to be found.
Right now here on forums this video together with the post is naming and shaming, thus I will remove it. It CAN be a botter but it is hard to say just judging by that video. Please leave the investigation and final decision to support. If they decide to not ban, there was no proof for botting that would "hold up in court" as a figure of speech.
Which should not stop you from reporting any suspicious activities.