I will add to the other 2 answers that sometimes we use "pass out" to tell someone we are going to sleep and very tired. Por ejemplo, If you are on the telephone with your friend, and the time is getting late, you could say: "Ok man, It's late and I'm tired. I'm going to go pass out."

Thank you all.

They are interchangeable, but it should be "...his mother black out." ..."his mother pass out" and "his mother faint."

Yes, however, we use the expression, "black out," when someone is drunk and does things they are not aware of doing at the time, or later, when they sober up. So blacking out does not necessarily mean falling down in the way passing out and fainting do. A person can be "in a black out" and still be moving around, dancing, driving, talking, etc., but still have no conscious memory of the events.

These words are all results of a sudden and strong emotion. The words "passes out" and "faint" can be interchanged but not "blacks out". Passes out and faints may mean that a person "lost consciousness". "Blacks out" may mean that a person becomes unreasonable and irrational mostly due to some event that causes extreme anger and strong emotions and that. "Blacks out" may look like "passes out" and faints" but "blacks out may also mean that a person has lost rationality and judgment to do right or wrong things towards another person.