You definitely don’t want to get these two phrasal verbs confused!
Pass away is an indirect way to say someone died:
Pass out has two meanings:
1. To lose consciousness
He was so exhausted and dehydrated that he passed out.
She passed out after drinking an entire bottle of wine.
2. To distribute
The teacher passed out the worksheets to the students.
There’s a guy passing out brochures for the new cafe on the street corner.