I heard one hadith that if one is suffering from some illness his sins are forgiven. I am suffering from AVN avascular necrosis for last 4 years. So do I come in that category, do my sins forgiven. What are the categories of illness comes under this.
Yes, if you bear it with patience.
“No tiredness, exhaustion, worry, grief, distress or harm befalls a believer in this world, not even a thorn that pricks him, but Allaah expiates some of his sins thereby.” (Narrated by al-Bukhaari, 5210; Muslim, 4670).