A Pepper Tree turned brown in the 117 degree weather.

Whwre exactly do you live. Unfortunately it does sound like this may be a fatality.

Either get yourself a book on pruning or look up pruning a Pepper Tree in your search engine. I tried to find an article using your question but there isn't much that I could find. One of the articles did say that it's important to trim a Pepper Tree the correct way or it will die.

I did google 'how to prune a pepper tree' to get you started. Here is the list of articles & video. If you have a California or Brazilian Pepper Tree, please change the search terms. They may be different.

https://www.google.com/search?q=how+to+prune+a+pepper+tree&oq=how+to+prune+a+pepper+tree&gs_l=psy-ab.3..0i7i30k1l2j0i8i30k1.46356.49742.0.51716.11.11.0.0.0.0.130.1140.6j5.11.0....0...1.1.64.psy-ab..0.11.1136...35i39k1j0i8i13i30k1.0.i_XFJe5L2KE

Sounds like it did not get enough water? I would get at least a consul with a local arborist for suggestions. Sounds like you have lost other trees. Maybe the arbrist can help.

Try using a slow drip soaker hose, around the drip line of the tree.

The drip line is where the farthest out branches would be able to drip water from a rain. That is where the finest roots are... the ones that are best available to take up water.

It worked for my English Birch, it was losing leaves in July and August, due to lack of water, during last summer's drought. It was looking like it was Autumn.