AP Physics II without taking AP Physics I

[skieurope]

From the College Board:

Students should have had AP Physics 1 or a comparable introductory course in physics. Students should have taken or be concurrently taking precalculus or an equivalent course.

https://apcentral.collegeboard.org/courses/resources/planning-new-ap-physics-courses

Additionally, the HS might set its own prerequisites. Without knowing the content of the summer course, I can’t say if the background is sufficient or not.