We need more details:
Is the coax cable from the wall hooked directly to the TV? Sounds like it since you have no cable box. If this is the case, the LG LCD will probably have a stereo out jack named something to the effect "Audio Out" "Monitor Out" - just feed this output to one of your receivers remaining inputs (Aux or Tape). Make sure you turn the volume down to 0 on the TV so your father only hears his surround speakers.
Lastly, tip of the day - get a high definition cable box. That 30" LCD (I assume its widescreen) deserves some hi def. I am pretty sure it will support it. Once you see Hi-Def there is no going back to Standard Def.
Is the coax cable from the wall hooked directly to the TV? Sounds like it since you have no cable box. If this is the case, the LG LCD will probably have a stereo out jack named something to the effect "Audio Out" "Monitor Out" - just feed this output to one of your receivers remaining inputs (Aux or Tape). Make sure you turn the volume down to 0 on the TV so your father only hears his surround speakers.
Lastly, tip of the day - get a high definition cable box. That 30" LCD (I assume its widescreen) deserves some hi def. I am pretty sure it will support it. Once you see Hi-Def there is no going back to Standard Def.