Yes - why didn't they take it to a vet?

If the kittens are too young for flea chemicals they can be bathed in
special shampoo - better educate your friend before their other kittens die.
Incidentally - I hope the kitten was still with its mother as 6 weeks is way
too young to be weaned?

Bring them and the mother to the vet for worming and anti flea
treatment!!!!!!!!!

With kittens, it's not going to be what little blood loss there may be from
the fleas, but from the heavy doses of worms FROM the fleas. A heavy load of
worms in a kitten can effectively destroy the digestive tract, meaning the
kitten gets absolutely no nutrients from whatever food they do eat -
horrible diarrhea, and a rather slow, terrible death.

So yeah. Tell your friend to get the rest of the kittens to the vet. Even at
six weeks, they should be safe for a small dose of capstar (which will kill
the fleas) and either strongid (which will get rid of most worms) or droncit
(which will get rid of most worms, including tapeworms).

And then tell your friend to get the parent cats spayed and neutered.
Shelters are struggling to find homes for all the kittens they get each year
as it is.