Well, depends on what broke. If your parents happened to jsut blow both speakers on the TV (most have two) at the same time (unlikely), then hooking up a soundbar would likely work just fine.
If the TV's internal sound processer bit the dust, then it might still not work.
Here's the thing - you need to hook something up to the audio out ports on the back of the TV.
The TV may have a optical out port like Monster alluded to - that would be the best option, sound quality wise, but requires that the external seaker solution you come up with to have an optical in capability (many sound bars do).
The TV may have the old red and white "RCA" plugs for audio out. This is kinda the default thing most likely to be there.
The TV may have a headphone out port. This would be the easiest way to test if the TV is capable of sending sound to a soundbar. So plug in your headphones or earbuds and see if you can hear. You might need to wander through the TV's setup options to turn on the audio out functionality.
If yout TVisn't sending a sound signal, you might stll have a solution by plugging in the soundbar to the cable box directly. But the TV remote might or might not be able to control that volume...
Soundbars vary a great deal in cost and performance. You could buy soundbars for as little as $30 I think a few days ago. Probably still under $50 if you look. They probably won't blow you away with their quality, but it is a step out of the silent movie range.
And then there are soundbars from the likes of Polk, JBL, Klipsch, Bose, JBL and others that will really knock your socks off. But those will be several hundred to more than a thousand dollars.
This right here is a great deal (at about $200) on a quality sound solution if you can set your TV on top of it. It is much deeper than a regular soundbar that you can mount under a TV hung on the wall though.
Edited by Pnambic, Dec 2, 2015 - 8:04 pm.