I don't think it was obvious, honestly. He had a pretty long proven past in PA that made him popular and pretty fairly progressive.
Also this isn't about near death. This is about debilitating strokes that literally kill off parts of your brain. Depending which region was harmed it can drastically alter your personality and perceptions. Eg, the ACC is a key component of the brain associated with leftism.
oh god we don't need a qanon for our side. it's not at all unbelievable that someone wanted to shoot this fucking guy, especially when everyone and their grandmother has a dozen guns in the US.