My dad's 26" Panasonic LCD has an HDMI port that is oriented the same way as your dad's, AvFan. UMtiger has a Panasonic plasma that has ports laid out similar to psyprof1's - and that plasma has a support bracket for the power cord that is similar to what I was talking about in my post yesterday, in the form of a clip.

If you could establish a support that carried the weight of the cable and kept upward pressure on the cable, that would work even if the jack is expanding. I suspect, though, that even without that the upward pressure, simply taking the cable weight off the jack will solve the problem.