Hypoxia

Oddly appropriate "handle" for one asking oxygen questions.

The question here is about the Bravo, not a theoretical single pilot jet. Yes, in a theoretical single pilot, a pilot could give and an another pilot receive dual instruction for the purposes of training in the specific type, not as a way of getting around the minimum crew in the TCDS.

As to O2 in the Bravo, I don't have an AFM, so pretty much a blank as to O2 consumption. In your example, there is no requirement for a SIC on that flight; oxygen consumption can't drive it. Second, there is no need to use 100% while in cruise, even if the FAR requires wearing the mask. As I pointed out, the dilutor demand mask will greatly reduce O2 flow by selecting NORMAL until a pressurization problem demanded 100%, obviating the entire problem. In fact, not breathing 100% is a good idea, physiologically.

Skypimp

Look up the TCDS, it is clear a Bravo is a two pilot plane, the time can be logged, whether the PIC is single pilot typed (if he is, I think that automatically means he can fly with a copilot under the FAA) or the plane is single pilot equipped. Now, flying with your brother doesn't look fishy, if anyone inquired.

That said, you will have to be trained, as required by FAR and the insurance company. Just sitting in the seat won't cut it. FAR 61 has the specifics what ground traing is required, what flight maneuvers must be accomplished. There was a Citation accident a few years ago that brough up all sorts of bad news about SIC training.

GF