brother: It’s very difficult to give general advice, but just try to impress upon him the gravity of doing inappropriate things. Depending on circumstances, asking that things like high-fives and taps on shoulders and such be avoided is impossible (even though by teenagers any contact is almost certainly Derech Chibah, except under rare circumstances). But if you can get through to him that being inappropriate with girls is a huge no-no, he’s much more likely to come out of this okay.
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