weber C still non weight bearing leg muscle exercises?

Hi - I sustained a weber C fracture of my right ankle about 3 weeks ago (16th may). it was operated on for ORIF and one screw was placed (18th, discharged 22nd). The fibula has no plate. one week ago the cast was removed and I'm in an aircast, however no weight is to be put on it until at least the 1st july. There is still a little swelling and numbness, and obviously it doesn't move much (although it moves pretty well considering and improves quite fast). there's no pain other than the top of the foot which has some swelling although that's going down.

My question is to do with wasting of my calf and other muscles.

I can't put weight through the ankle. But is it safe to e.g. put moderate weight on my heel (lying on my back) and lift my body gently using my legs and arms.

just in general is there any exercise I can do at this non-weight bearing stage to regain/maintain some muscle strength and tone in my leg without jeopardising the recovery from the injury.

It's healing well now but I understand this is a serious injury with a long recovery. the main priority is the injury and in terms of physiotherapy ensuring I get full movement back in the ankle. I'm a bit shocked how quickly my calf is wasting however so if there is anything I can do, I'd like to try.

My general level of fitness and physical confidence is relatively low. I've never been athletic. I'm moderately though not seriously overweight.

many thanks