For somebody with Parkinson's this is still likely or impossible to achieve, @Realistic_build_Speed likely to be not easy, but could you take a photograph of the system as it is at the moment, it may give the collective a better idea to come up with a solution. My B-I-L has quite severe Parkinson's so I do understand the issue maybe a little more, but I think the hinge method has to be the way forward. Then with a rope to pull to lift the section up, this needs to be accessible from both inside & outside of the shed, ideally a motorised lift so all he has to do is press a switch to get it to lift & comeback down.