My friends 8 week old pomerian mix puppy died today and we dont know why. ?

Yesterday the puppy slept all day, and when waken up the puppy just fell back to sleep. It woke up this morning took a normal poop then laid down and started throwing up foam and died shortly after. They have no idea what happen to her, there are two other 8 week old puppies showing no signs of being sick, I know someone out there would know. And please don't tell me to call a vet, I wanted to try this first as I have found yahoo answers very helpful in the past