It's slow and difficult to critique a video like that properly, based as it is on personal narrative, because it is deliberately made so that things are not presented as outright lies, just misleading and loaded. It would take me many hours to drill down and locate specific issues with it and I spent too much time on this already - I have electrical things to do!
As an example, look at the first 30 seconds. The guy says he grew up among native American people, and that one of them told him to take his shoes off because they would make him sick, and that at the time he didn't know why that would be. These are presented as though they are significant facts, and there is no reason to doubt them as facts. However, he does not say that the shoes made him sick, or that the person who told him had reliable evidence that they would make him sick, or that if they did make him sick, it was due to an electrical phenomenon.
This narrative is there to plant a seed of an idea, to get your curiosity aroused, so that when the link between sickness and grounding and shoes is later broached, you recall those 'wise words' and make a connection by yourself regardless of whether there is one or not. You infer that the native American knew through folklore that insulative shoes make you sick and now you seem to have a scientific reason for it, and you have used your powers of analysis to corroborate two independent sources to improve the reliability of your data. But actually, it's only one source, the guy who wants to promote his views on grounding.
"In simple terms, grounding is literally putting your bare feet on the ground."
Simple, but in an electrical context, not correct.
"Mother Earth is endowed with electrons." True, but misleading, as all neutral matter is endowed with electrons, including synthetic rubber shoes, the air, your body.
"These electrons are literally absorbed through your feet." Borderline false. Some exchange of electrons might occur but there is no net flow of electrons without electric current, and he does not state that they are absorbed through your feet only if you connect yourself to a source of a potential difference to drive the electron drift against the resistance.
"It's like taking handfuls of antioxidants." False. Antioxidants can participate in chemical reactions in which electrons are exchanged, but the mere presence of electrons does not cause the same chemical reactions.
I have to get on with some work now...