I remember details from a sci-fi book I read years ago, but haven’t been able to identify it by searching on my own. Hopefully someone out there has better recall than I do! The main points I remember:

• The main character (or possibly his brother) suffers from a condition where his vision (and possibly some other senses) are time-lagged. He essentially sees what he was looking at a few hours (or maybe even days) ago, which makes it impossible to support himself.
• This condition seems to be somewhat common in the book, usually a result of proximity to a warp gate or similar sci-fi travel technology. the length of time-lag increased as it worsened. It might have been called Gate Sickness or something similar.
• I’m fuzzy on the plot details, but I think this sickness was a catalyst for the brother of the afflicted to leave their home planet searching for a cure.
• I haven’t read many short stories so this was probably a full length novel. I read this in the early 2010’s but I don’t think it was a new release then.
• I found a somewhat similar previous question (linked below) but none of the stories in the answers or comments are a match.

Old story about a man with "vision lag" -- he sees what was happening a few minutes ago