I regularly use my GPUs to upgrade the wife and kids. My 4 year old and 7 year old always appear near the top of the list along with my wife and myself. I'm a GS so it may be a different mechanism... but it seems that for the purposes of the upgrade, they are getting some preference. But that is ONLY when I travel with them. If they are alone, they languish at the bottom. When they are traveling alone, I usually try to find them a saver business reward.

That said, SFO-SIN might be a VERY tough route to get. You may have better luck with SFO-NRT-SIN