Yes everyone knows front disc are better, but is he upgrading because the drums aren't adequate there not on par with his driving style, have they failed regularly/once and cause near misses my guess probably not ? Rear disc aren't a needed mod.
If OP just putt around town drums are fine. If he does high spirited driving though the twisty and or long steep down hills with lots of braking then yes, especially if they maintained and not giving the performance needed. But if it's just to do something to the car it probably isn't necessary but it's his money and there's worst things to spend it on.