It is unusual that dogs would die from acorn poisoning. We see it more commonly in cattle. Dogs rarely eat enough quantity for them to get a toxic level, they usually get just a gastroenteritis so you will often see signs of this before you would from acute kidney failure. Dogs are also lucky that they tend not to chew the acorns so the toxins aren't released as quickly. However because of this they may be more likely to get a foreign body intestinal obstruction!
For treatment it is usually supportive care.... fluids (iv), antacids, and a bland diet.
In terms of reccomendations my best advice would be to rake the yard daily ( Yes I know not an easy feat) and supervise them to minimise ingestion. If they do ingest any watch for signs of intestinal upset and get your dog checked out by your vet. If you know he did eat some you can always try to bulk out his diet to try and pass them through quicker ( you want high fiber so try adding rice or using a commercial high fiber pet food)