Stubborn father has a red eye, half the eye is red from eyeball to corner of eye towards the nose. refuses doc, no vision issues. going on 5 days?

He's probably right: If bright red (like blood), and no pain or other symptoms, it's probably a subconjunctival hemorrhage, i.e. a small broken blood vessel. It can happen from normal eye rubbing. It probably will clear up very soon, and quite suddenly. He'll probably wake up in the next couple of days with an entirely normal looking eye. In that case and if it doesn't happen repeatedly, he (and you) can rest easy.

Blood shot eye: If it is blood red, and no pain/vision changes, it sounds like a subconjunctival hemorrhage, which is a burst blood vessel under the skin of the white of the eye. It is more common is people who take aspirin or blood thinners. It is almost always benign and usually goes away in 1-2 weeks.