Why would he use the outs on the TV? If he is going to use an amp, use the optical out on the 721.If you are talking small amplified speakers as used with computers yes they will probably work but don't expect a hughe increase in sound quality. If you just want to plug speakers into the jack no they will need an amplifier to power them.
Look on the bottom/back of the TV there is probably a set of RCA jacks labeled audio out, these can be used to send sound to a surround sound amplifier.
Get the SoundsWorks system from hifi.com for a really cheap boost ($80). It is a pair of mini speakers and a mini subwoofer designed to use with a PC and had volume control and a mini jack. You may need a mini jack adapter but it should work great and improve your audio a lot.Is there a way to utilize the earplug adapter oon the tv to get stereo speakers to work?