My Husband Has Noticed Blurred Vision, Fatigue, Stomach Pain/cramps "tingling"

My husband has noticed blurred vision, fatigue, stomach pain/cramps "tingling" &/or a jittery feeling over his entire body, that is not anxiety. "Crusty" eyes throughout the day, similar to what ppl say when they wake"I have sleep in my eyes", but this goes on all day as well. These issues started 3-4 weeks ago. Any thoughts?