Ahem, that would be "life as we currently know it". Which is something very different than "impossible". Your assertion is premised on your conclusion.
The vast majority of other parameterizations for the universe will allow mathematically equivalent constructions of life, which is about as close a comparison one can make as mapping some kind of physical equivalence between differently parameterized universes is meaningless on many levels.
You cannot make a martini if you are given beer as your only ingredient, but the beer will give you a buzz just the same.
No, they cannot, not the parameters I am discussing. I suggest you try to understand the subject before making assertions.
The 6 numbers Dr. Rees refers to define the very structure of the universe. The slightest variation of them would prevent atoms from forming from plasma; or they would prevent any atoms of any other type than hydrogen from forming; etc etc.
No life of any form could exist in pure high energy plasma because there is not enough complexity. There would be no gravity waves to begin to cause coalescence etc etc....
Or imagine a universe in which only hydrogen, or perhaps helium also, exists.
Or imagine a universe where no stars exist. Only dust, barely above the absolute freezing point.
Life cannot be created in these conditions.