As a physics professor, I can confirm that you are correct about getting into a good graduate program. It is more about your performance and what you do to prepare yourself. There are plenty of Ph.D. physicists coming out of LACs. However, if his school does not offer a full complement of core courses, then his preparation might be a bit lacking compared to someone coming out of a program where the courses are offered every year and full sequences are offered.
For example, the best prepared students usually have 2 semesters of Classical Mechanics, E&M and Quantum Mechanics at the Junior/Senior level and one semester of Statistical Physics at the junior level. The best students at my university, Illinois Tech, even take graduate courses in their Senior year and they say that really prepared them very well for graduate programs.
The other aspect that might make it advantageous for him to transfer is access to sponsored research programs and working close to graduate students. All schools realize that research experience is key to making a good graduate application and there are opportunities at every school and clearly there are nationwide opportunities at REU programs in the summers. However, being able to work on a funded research program during the year is sometimes a plus.
As for getting into the schools you mention, I really do not know. Some schools will expect you to transfer only after the first two years and may schools do not offer very generous financial aid to transfer students. You need to call and ask what the transfer parameters might be and see what aid might be available to make it financially doable.