Ask your cousin to go with a good lawyer. A good lawyer knows how to grease palms and expedite things
Where has the cousin’s wife died? At home or hospital? If it is a hospital, then ask your cousin to get originals of all the documents from hospitals – reports, bills etc
How long were they married?
If your cousin’s wife’s parents have filed a complaint under IPC304B, it is the worst nightmare for any husband in India today. In that case, only God or a very good lawyer can save him