It is acknowledged on all sides that President Trump cannot be indicted. But that doesn’t mean his son can’t. In fact, Mueller would be a fool to not do so. The case against him is very strong. He was at that June 2016 meeting with the Russians and later admitted that he was there for the purpose of getting dirt on Hillary:
A meeting between President Donald Trump’s eldest son and a Russian lawyer during the presidential campaign occurred at the behest of a Moscow-based singer with family ties to Trump’s businesses, according to a participant in the talks. Donald Trump Jr. acknowledged Monday he made time for the meeting hoping to get information about Democrat Hillary Clinton.