No amount of fundraising is going to increase the amount of helium or other rare elements on the planet.
Helium is an element, a by-product of the natural gas industry.
An element cannot be made by man. It's not a compound to be manufactured and cannot be created using any method. When it's gone, it's gone. There is no more.
Hydrogen is smaller and less dense, but it is so reactive, that it combines with so many other elements and chemicals, it's easy enough to stop it from leaving earth's atmosphere.
Helium is one of the inert, noble gases. It's so stable, that it does not react with anything and, therefore, escapes earth's gravitational pull. It can rise into space through our atmosphere.
Throwing it away inside a balloon which could, additionally, choke and kill wildlife is just wicked.
Chinese lanterns are fire hazards and the metal parts also cause deaths by lacerating animals' mouths or by being another choking hazard.
Demonstrations of grief should be for funerals and memorials.
Wrapping environmentally destructive flowers in sheets of non-recyclable plastic film, tying teddy bears made of non-biodegradable fabrics to railings and lamp posts and sending balloons into the atmosphere won't do anything except do more damage.