What you heard about players majoring in certain programs is correct. The demaands of bb and the bb schedule sometimes make it virtually inpossible to be involved in classes that require extensive lab time.
Now basically is the time that your son needs to decide which path he wants ot take for his future. Has noting to do with playing beyond college. There are sacrifices that have to be made, and one of them is deciding upon which major your son will follow, if involved in baseball. Business,mamagement, communications seem to be a great fit for many players. While harder more difficult majors can be managed, something might suffer eventually.
If your son is interested in government, have him investigate schools that have a msjor in that field and a baseball program. Just a suggestion. And this is a good question to ask during the recruiting period, about his inteneded area of study.