The rockers are structural support 14 gauge or about 1/8 th inch thick. With the inner rockers they form a box beam. They are not too expensive to buy a replacement pair for the models available aftermarket. This is one of those jobs to do yourself if you can weld etc.
I gave up patching anything structural in nature years ago. That is unless the area was very localised with unrusted really solid metal close by. After examining a couple of rusty cars that had been in bad accidents it sure changed my mind in a hurry. Semi cosmetic quality repairs in structual areas are not for me.
The direct cause of my neighbours wife death was rusty structural components as well. I was asked to do some repairs on the car about three months before that. I told her husband there was no repair possible And the car was finished. . Although since we had the stretchers and shrinkers I let him make a convex panel up for above the tailgate area to keep the water out. He was not totally auto illiterate. The car had even roof rotted. Basically he made a bad decision that resulted in his wifes death.
Also to be fair we live in a climate here with lots of salt on the roads in the winter plus airborne salt it seems. Thats if you live right next to the ocean. So our corrosion when it occurs can be far more severe than the north american average. When the jackpoints are fairly bad there is usually more severe rust in otherplaces. Not always but just usually here.
Some cars here have just been turned into primarily oxides of rust held together by the undercoat. On my cars I always spray oil into closed areas to help hold things off. Only if there will be no work done in the area though. Closed spaces like the rocker boxes with no internal protection just seem to promote rust. Yet a mix of grease and oil sprayed into them through drilled holes in the bottom will make them outlast the car. The amount of internal coverage is not important as the oil portion creeps all around in there. Oil base products seem to be the best at keeping pre rusted metal and oxygen apart. They also tend to allow no moisture between the oil and metal. The plastic plugs to seal the holes afterwards are cheap and available at most car part places.