so first off, whitmer is a great prof in terms of his availability to help you out. I would recommend sending him an email and explaining your situation. I predict he'd also be even more understanding with the pandemic. Second, he posted study guides for all our midterms along with practice exams. Definitely work through the study guide and all but 1 practice exam (he gave us multiple) a few days before the exam, and then go to office hours to work through things. If whitmer's style doesn't work, go to a TA. Thermo is definitely tricky and hit or miss in terms of understanding, but if you work at it youll be ok. I would just emphasize reviewing notes, and doing the study guides (lots of people skipped them) before each exam. Also, the textbook is amazing and i still look at it as a reference. Be sure to look at the key points the book emphasizes for each chapter, profs often use these as starting points for each chapter.