Crossfeed for hearing loss

I’m afraid I can’t help you to solve this but what you need is a kind of combination of two existing technologies.
Room-correction – this alters the frequency response of a system. This can be used to boost anything above 6 kHz so can extend the hearing a bit at the bad ear.
Cross-over: normally used to split the audio between a woofer and a tweeter so anything > 6 or 8 kHz should be split and feed into the good ear.
This preserves the stereo image as much as possible

Then a mixer to combine the signal to to good ear with the > 8kHz of the other.
Maybe cascading a couple of VST plugins can do the job.
 

I have a similar situation with you. I have some (about 7 dB at 8KHz) hearing loss to my right ear. 

I am always frustrated by the stereo image that I am hearing. I always tend to tilt the balance of the sound volume to the right with the balance knob. Unfortunately it seems that the value of tilting needed is not constant, but depends of the song!

I do not see how crossfeed  can help us. I think that frequency equalization with different settings for each ear is the answer to our problem. I have try the FABfilter proQ plugin (there is a free trial) because it has the capability of different equalization settings for each channel.

Unfortunately, I have discover that just applying the boost that (in theory) I need (7dB at 8KHz) tilts the stereo image to the right! It seems that my auditory system is compensating some of the hearing loss I have. So I experimented with various settings and I found that about 3dB is the best compromise. 

Even with this setting stereo image is not always centered. 

Hope that it helps...

Might be volume related as the sensitivity of our hearing alters with the loudness.

Maybe you should try to generated an equal loudness contour of your hearing and use a parametric equalizer to generate a target curve.

It is possible that the bands of the EQ you are using are too broad.