Easy reading westerns for my Dad

My Dad was recently in an accident. After many months, he’s doing much better but still in bed most of the day in a care facility. He’s so bored and can only read for a little while before his eyes get tired. He has always read mostly westerns. Trying to send him some lesser known books that he hasn’t read that are not too long. Any suggestions?! Even better if they take place in Colorado/Wyoming.