Oh yea, one more thing to consider!!
Medical school is a LONG process. So, the sooner he starts, the sooner he will be able to "get on" with his life. Many doctors put off getting married and having children until after residency. The sooner he enters school, the sooner you can have grandkids (okay, just kidding :))
But really, it is very long and very expensive. Many doctors end up with lots of money in loans, so the more you save on the front end, the less loans he may need to take out on the back end.