Lately I have been seeing on linkedin that many friends (Capital Markets and Mergers and Acquisitions teams) have been posting that they have provided legal advice to CFOs and promoters of various listed companies on many complex transactions.

Is it true that A0s in Tier 1 work with CFOs and promoters and they take legal advice from them?

When they write that they advised someone, it doesn't mean that they did it themselves. They were a part of the team who made that advise.

Bhai linkedin is a full on flexing forum.