Presumably he's had a look here?
https://www.healthcareers.nhs.uk/explore-roles/allied-health-professionals/roles-allied-health-professions/physiotherapist/entry-requirements-and-training-physiotherapist To get onto a physiotherapy degree course you usually need two or three A levels, including a biological science and/or PE, along with five GCSEs (grades A-C), including English language, maths and at least one science. Searching for courses on the UCAS site and filtering on 120 points (BBB), there are quite a few universities at that level, but quite a few also at 128 (ABB) and some above. I didn't look at any institution's specific subject requirements, though. But going on the statement above and, as you say, there is overlap between PE and Biology, so if 'straight' Biology feels like too much of a push, he should be able to substitute something else there.