Thank you for the detail in your question. It sounds like you have covered all of the follow-up questions I usually ask. I believe the redness of your eyes is most likely from dry eye. Dry eye is almost universal in patients over 80. The lids scrubs and warm compresses you have been using will help well with eyelid problems such as blepharitis. I would add artificial tears to your daily scrubs.
Artificial tears have no medication but help as a lubricant and supplement to your own tear film. In cases such as yours where no other eye disease is suspected the artificial tears should help with redness after a few weeks. I should be available to answer any follow-up questions you may have. Please consider leaving a positive rating when your question has been answered fully.