My son chose Northwestern over Brown for Biomedical ENG, Now he is worried if he made right decision

The OP and his son live in Georgia, and son was accepted at Georgia Tech where he would have in-state tuition and much better weather, and he turned down GT for Northwestern?! U.S. News ranks GT as #3 in BME, Northwestern not even in the top ten. I realize USN rankings aren’t always the “final word” in college rankings, but GT is very highly regarded in BME by all relevant ranking entities, including engineering-specific ones. If given a choice between only GT or NU, I would pick GT with absolutely no hesitation.