Which way do the rafters run? Parallel to the door opening or perpendicular to it.Well, my current span is 22.5" and it wouldn't change if I hung a new header or? Not sure what my roof material is. My roof is 5/12 22.5 degree pitch. The rafters are 2x4s. What is a structural ridge? My storage expectations are minimal. I'm not planning on putting a lot up there.
If the gable is above the door, the roof load will be different, than if the gable is over the adjacent wall.
Your buddy is mistaken, that a couple of 2X12's will be adequate for the span.
As previously mentioned it will require a engineered beam!