There's a very high probability that Dad will love Char-Broil's RED 580 infrared grill. A Home Depot exclusive, it has four burners that use infrared heat to handle just about anything he'd think to throw at it, within just about any temperature range, and its stainless-steel exterior is mighty easy on the eyes.
You run the risk that he might love it a little too much, though, as there's also a very high probability that everything you eat for the foreseeable future will be cooked on Dad's new grill: steak, potatoes, cereal, toast, pancakes, sandwiches, plantains, rice, coffee, salad you name it.
Not that it's a bad thing. Just something to think about.