Haha my dad is around your age and always seemed to be somewhat red colour blind. He has much better vision than me ironically but he definitely has trouble with blood trails I can point out an obvious patch of blood and he wont see it at all. He has become very proficient at reading trails to the point where he can find the deer without a blood trail with ease. My best advice would be to take it slow, carefully inspect spots that look wet and even bring a tissue to swab it to see if it's blood, but don't forget to mark every spot so you don't lose where you were! But most importantly watch that deer like a hawk after you shoot it to see the direction it went, if you know the direction you can follow the game trail.

edit: we did buy a seek thermal xr (one of those thermal cameras you attach to your phone). It has been a huge help on occasion but most shots were very clean so the deer were usually found shortly after.