Drexel Combined BS +MD or Undergrad at Boston University

Too many numbers get tossed around as if they were facts: so a question-what is the basis for the following statement
“acceptance rates for med schools are 3-4%; harvard and MIT for undergrads are 5-6%”?

And where does the 90% number come from? It wasn’t on Drexel’s website-in fact, they state that they can change standards basically without notice.
It appears that both sets of numbers are based on “somebody I know said…” Is there any empirical evidence to support either?
And in this case, what everyone seems to be ignoring is the fact that OP has stated that her son doesn’t think that Drexel is “a good fit”. This alone ought to give OP pause, because it seems, simply put, that her son doesn’t want to go to Drexel.
From the Harvard pre-medical booklet, which I skimmed quickly; couldn’t find the 3-4% acceptance rate:
" Do not believe all that you hear (or that you read online).
Misconceptions and misinformation can provoke unnecessary anxiety. This booklet is designed to help "
https://ocs.fas.harvard.edu/files/ocs/files/premed-academic-publication.pdf