neither
either get a male his own tank 2 gallons or more
or a 10 gallon tank with around 6 or more females
or a female by herself in the same size tank as the male
the reason being because at the end of the fight, there will either be only the betta, or the original fish subtract a few
I wouldn't recommend he gets a male/female combo first up, they are usually INCREDIBLY hard to manage, especially for a beginner. A female community may also get a bit bitchy.
The individual fish in a 2+ gal tank idea sounds great!