About 7 or 8 years ago there was a cat full of men, possibly college alumni, mid 30ish. One of the men was in a wheelchair. They rigged a bosun chair to drop and retrieve him from the dinghy. His wheelchair had big fat tires and he went everywhere. We saw them several times and marveled at how they made his trip safe and easy for him. Just take it slow and easy. A gait belt might you just enough control getting in and out of the dinghy for both of you to feel safe.
https://www.amazon.com/Prestige-Medical-621-wht-Cotton-Buckle/dp/B000V4SV5G?th=1