Partial mash refers to the use of some grains as well as extracts as your sugar source, not the size/amt of water you are using. Perhaps his stove cannot handle a full boil or he does not have a way to cool five gallons of wort quickly?
Primary1: Pliny the Elder Clone
Secondary1: Blueberry Wheat
Secondary2: Cherry Wheat
Keg1: Blue moonish Clone
Keg2: EdWort's Kolsch
Keg3: Bell's Two-Hearted Ale Clone
Bottled: Pumkin Ale, DFH 60min, Choc Stout, Choc/Coffee Stout, Apricot Ale, Banna Foster Cream Ale, Christmas Ale.