In general, a question like this depends on a lot of things...his current GPA, how hard his other classes will be the coming semester, how good he did in Physics 1/how good he thinks he can do with a bad prof, how much it will hurt his class "plan" to push it off, if he can take it in summer/another quarter with a better prof, etc....
Personally, the quality of the professor was a very big thing for me when I scheduled my classes. I really think my first quarter orgo professor (I had the choice of 3 profs) set me off on the right foot and helped my success in the folowing quarters. This doesn't exactly apply to you, but you should consider the miserable factor vs. the I wanna get it over with factor. My favorite pre-med classes all had to do with the prof. On the other hand, I love bio as a subject, but had an atrocious bio professor for 3rd quarter...luckily it was summer and I only had to have her for 3 weeks 🙂.
"wolferman has a good point; make sure that you take at least two semesters of calculus-based physics before applying to med school. "
Um, I am not 100% sure for all schools but non-calc based physics is ok, if you are a non-science major. I know of 100's of premeds at my school who do this every year.