Hi Corey and welcome
First, if you could please tell us where you are, that will help with ideas on how to save the trees. Different soil types drain differently and if you are in Florida, most of the soil is pretty soft and sandy.
Yes you sure did shock those trees by driving all over their roots with some heavy equipment. Roots of those trees don't go straight down, they spread out fan-wise near the soil surface in a circle around the tree that is usually wider than the spread of the branches. So whatever you built there with the concrete pad (a well?) may be on top of some of the tree roots, and you've torn or broken a lot of the tree's surface roots with all the driving on top of them.
Also, there's standing water in your picture - did you get a lot of rain recently (if in Florida I know you did) and did the area flood? That may or may not be a bad thing for the trees but having the water standing there is not great for the health of the remaining surface roots.
Fertilizer isn't going to help, and may actually harm the trees right now. They aren't growing or taking in much nutrition right now as indicated by the dead leaves. I know it's a difficult thought, but I'd be inclined to just wait a couple of months and see what they do. But keep the vehicles away from now on!
If they've died already, it's too late anyway, but if they're still alive and just in shock doing a whole bunch of stuff like pruning or fertilizing isn't going to help and may do harm. If they put out new leaves and start to grow again, then consult the arborist about having them pruned to remove any dead branches (or do that yourself) but don't let some hack tell you to "cut it way back" which in gardening circles is known as "hat racking". It's a terrible thing to do to any tree and one that's had a shock will not respond well.