Complex sentence: Neelakantan (Mohanlal) is the heir to the well known Mangalassery family who squanders away his father's largesse and good name, but is loved by the people who knows him well.
Split into simpler sentences: Neelakantan (Mohanlal) is the heir to the well-known Mangalassery family. He squanders away his father's largesse and good name, but is loved by the people who know him well.