50 lakhs cash in hand, where to invest

My father liquidated our shop because it was not yielding expected rent and the area it was in had no prospect of future growth.

What is a good way to invest and diversify these 50 lakhs? Considering that these are a significant chunk of my father's life savings and not something to play around with (like investing in crypto)

Edit: I think some of you are assuming my father is retired, he's not, he has a job, I'm currently in college, we're dealing with this kind of cash for the first time that's why I'm asking for advice

Edit 2: Cash is in bank, not physically in hand, slightly misleading title I'm sorry.