Complex sentence: It was surprising that he did not suffer a worse fate, some theorize that this was perhaps due to his political opponents still holding him in high regard-but more likely his drastically failing health had much to do with it.
Split into simpler sentences: It was surprising that he did not suffer a worse fate. Some theorize that this was perhaps due to his political opponents still holding him in high regard-but more likely his drastically failing health had much to do with it.