My wife has worked in higher ed for many years, largely with Title IX and campus safety/harassment issues, and passes this along:
Criminal charges are not in the power of the university, even the university police. Under TIX and MA State law, the school cannot intervene in any sort of criminal case. Whoever the reporter/complainants are, they get make that decision.
Now, they say sexual harassment/professional conduct and not TIX, which likely means that his conduct was either NOT criminal or it didn’t happen on Harvard property.
Probably, this guy was your standard issue sex pest, with some mix of disparaging, sexist, homophobic jokes, weird creepy touches, inappropriate comments who spent several decades treating the student body as his personal dating pool.
Academia is FILLED with these guys.