Agree with Steve that you are to be commended for assisting the slowest member.
In fact, your continuation from intended campsite at 8000+ft all the way to Lone Pine may have even been just as important as what you did up high.
The mantra is that descent, descent, descent cures AMS, HAPE and HACE, but many people do not realize that some people CONTINUE to deteriorate even WITH descent. Furthermore, the height of Whitney Portal is above the official definition of high altitude and altitude illness(8,000 ft), so your Houston friend was still in the danger zone. He might have done well stopping at the Portal, but when ill, descent as far as possible is sometimes needed.
The medical facilities in Lone Pine get an occasional patient who has not recovered with descent. While hypobaric hypoxia is the cause of altitude illness, sometimes the cascade of cellular mechanisms (like fluid shifts and inflammation in lungs and brains) keeps on going.
Well done.
