Not being negative on Euro per se- more the AP part. Limiting your search to AP classes could mean passing up classes that are just as good- or better- but that don’t have the “AP” designation. Look for online history classes at the 100 level at places like UMass Amherst, ASU, UMd, etc and see if there are ones that are interesting and work with his schedule. But: it won’t be free.
Another path is to take an AP class that is available in his school that will knock off a gen ed or pre-req requirement at the university he is likely to attend.