meirman wrote:

A friend's house faces west and it gets so hot in the afternoon that
his rather new and just recharged central AC can't keep up with it.
Much hotter than other places. Cathedral ceiling.

All I can think of is anti-heat window film...

You might consider screens made with 80%-sunblocking black shadecloth.
Greenhouse suppliers sell it in wide rolls for about 20 cents/ft^2.

Nick