Pelvic instability after femur ORIF (waterpolo player)

Hello. I am looking for advice...I am a final year student doing my final prac exam soon.
My pt is a 17yr old male, involved in a MVA 2 1/2 months ago. He is a waterpolo player. He fractured his femur (upper 1/3 shaft) and ankle. They fixated the femur with an intramedullary nail, but incision was laterally, over glut medius and ITB (I don't think TFL was damaged). Ankle was put in POP only. NWB 6/52. He is now on 1 crutch and moonboot during the day. Afternoons he only uses crutch. He complains of limping and weakness in his affected leg. He has a very bad limp, and walks in abduction with affected leg. Shortened stance phase on affected side, with severe abduction of affected leg during gait. Decreased knee flexion in gait and PF & DF are limited due to ankle fractures & immobilization.

However, his muscle strength is not as poor as expected on affected side and he is able to walk without crutch if need be (balance poor).

My diagnosis was confirmed when I was told by a qualified physio that his main problem is hip instability (glut medius). Any ideas on improving hip stability esp glut max & med will be appreciated. Hydrotherapy?? Hip abduction ex's such as single leg circles?

Thank you!
Danielle