Note that lawyers can come from any undergraduate major background. However, law is generally said to be very law-school-prestige conscious, with weaker employment prospects for those from non-top-14 law schools (see http://www.lstscorereports.com/schools/ ), and law school admissions is mainly based on GPA and LSAT score (see http://lawschoolnumbers.com ).
If chemical engineering really is his strength, such that he earns a high GPA in it, and he aces the LSAT, then he may be able to go to a top 14 law school if he decides to do that. Note that having an engineering background behind a law degree opens up some additional possibilities like patent law.
Of course, engineering degree programs do require some humanities and social studies courses, where he can take courses that can satisfy his non-engineering interests in debate, politics, sociological issues (racism, gender, (self-)segregation, etc.).
Note that many of the HB schools are a legacy of legally mandated racial segregation in education. However, the self-segregation aspect comes in to play today because relatively few non-black people seem to be interested in attending a HB school. The FAMU - FSU joint engineering division is an example. Despite the obvious arbitrage opportunity (FAMU is less expensive and also has bigger scholarships like the automatic full rides) for the same engineering education, most of the enrollment in the joint engineering division comes from FSU.