Here is more information and a quote from the guy himself who used helium in such a way:

“At one point I was looking up at the balloons, they were popping, the chair was shaking and I was looking down at my feet dangling through the clouds at a 747 flight taking off and a few landing,” Boria told CBC News. “It was incredible. It was the most surreal experience you can ever imagine. I was just by myself on a $20 lawn chair up in the sky above the clouds.”

While it’s tempting to write off Boria’s marketing stunt as a reckless prank – which it clearly is! – a fair amount of science-backed groundwork went into pulling this one-of-a-kind balloon ride off.

The cleaning products salesman spent a reported $20,000 (some of which went on banner plane advertising) and two years planning the adventure, sourcing massive 2-metre-high balloons capable of lifting his weight off the ground. And even then, he required 110 of them to hold him aloft.

Glad everyone is ok and this is the power of science 😉

here is some info on helium characteristics by wikipedia:

In the perspective of quantum mechanics, helium is the second simplest atom to model, following the hydrogen atom. Helium is composed of two electrons in atomic orbitals surrounding a nucleus containing two protons along with some neutrons. As in Newtonian mechanics, no system consisting of more than two particles can be solved with an exact analytical mathematical approach (see 3-body problem) and helium is no exception. Thus, numerical mathematical methods are required, even to solve the system of one nucleus and two electrons. Suchcomputational chemistry methods have been used to create a quantum mechanical picture of helium electron binding which is accurate to within < 2% of the correct value, in a few computational steps.^[44] In such models it is found that each electron in helium partly screens the nucleus from the other, so that the effective nuclear charge Z which each electron sees, is about 1.69 units, not the 2 charges of a classic “bare” helium nucleus.

thanks to Science Alert for the great writeup

thanks to Tom Warne for the awesome pic