Sorry for the double post, I put this in the ask a question forum, but I thought it might be better answered here.

I have about 15 - 30 year old oaks in my yard. I'm far from an expert, but I'm told they are live oaks. Recently I've done some construction nearby and "shocked" one of the trees. All of the leaves have browned, but not fallen. There are 2 of them side by side, no more than 6 feet apart. I think it's safe to say their root systems share the same space. One of the trees leaves browned, but it dropped all of the leaves. The other hasn't dropped them, and it's starting to lose some bark. I've contacted an arborist, but the treatment for the tree is going to be over 700 dollars, which I just can't afford right now. I also contacted my local fertilizer dealer, and they made reccomendation on several products to use. I just don't know if the tree is too far gone. It's been about 2 months since the leaves started browning. I've attached some pictures. Need some help, I don't want to lose the trees

Did the trees start their leaf troubles before or after heavy equipment was moving over their root systems?

You can tell if an oak is a Live Oak b/c it is evergreen. Not sure, but I think it is the only oak that keeps its leaves year round. Those trees are awfully close to each other and you're right about their roots sharing the same space. Oak roots spread out. I am always surprised how far the roots of my Red Oaks go. Anyway, I think you should google Oak Wilt Disease. It affects Live Oaks and Red Oaks (makes me paranoid). It can spread for blocks. In the late 80s or early 90s Austin, TX had an attack of Oak Wilt Disease and lost untold numbers of trees.
Is your arborist a certified arborist? And what is he proposing to do for $700? What, specifically, did your local fertilizer dealer recommend?
You definitely have some dead branches. And where there are the rust colored area, can you see any insects?

@tx_flower_child Joan, some of your questions were answered in this duplicate thread in the Ask a Question forum.

The thread "Oak tree not doing so good" in Ask a Question forum

@sooby - oops. Should I leave this be or delete it, assuming I can delete it?

I'm not sure, you weren't to know there was another thread on the same topic. I don't think it's possible to delete a whole post, although you can delete the text of it. You might as well leave it I would think, and if you have any thoughts based on the extra info in the other thread you could add to that there.