Chewing gum and helium experiment

There is a YouTube video about an experiment with gum and helium, creating a balloon that can lift a person.

Using the law of hydrostatics, the driving force must be at least equal (as can be seen in a certain part of the video) to the weight of the man with the balloon..

So,
P = I
Replacing the weights by m g and knowing that


we have

The mass of the man will be

Substituting the values
  and

we obtain

and we can drawing the graph m_H = m_H(R)

We have, for a mass exceeding 65 kg, the diameter of the balloon will be greater than 5 m. Therefore, by observing the video, that isn't the case.

The person has a high less than 2 m, the diameter of the ballon is much less than 2 m.
So the video was fake.
Versão portuguesa