check the grounds, check the main fuse box and see if everything is tight and also check the fuses. if it is just his instrument cluster then there may be a short in it. plug another cluster in there and see if it still does it. also see if there are any loose wires or anything aftermarket wired up in the car. Heck even shake some of the wires behind the dash as the car is running and see if you can pinpoint where it is originating.