I think Scheller is acting impulsively and reacting to events as they occur. I think he's driven by emotional pain and doesn't have any coherent strategy or plan. When you take on the USMC, never mind the Washington defense establishment, you should acknowledge a strong possibility of failure. You need a Plan B for the rest of your life, and probably Plans C and D. I doubt if Scheller has a credible Plan B. It strikes me that his behaviour is self-destructive. I suspect that he is also being 'encouraged' by various third parties and has been lurching mentally between different courses of action.As for Col Scheller, he's made it very clear that he knew that speaking out would end his career and stop his pension. "Unwell" might cover his frustration at having done multiple tours and seen his comrades die and lose their jobs over far, far smaller f*ck-ups than the withdrawal from Afghan and the behaviour of Milley & his ilk.
From his body language and statements, it seems like Scheller is suffering from an anxiety disorder, possibly PTSD. He's clearly under enormous strain and his natural courage and bravery may be a double edged sword at this point - in the sense that it propels him into further ill considered actions.
I think he's unwell and needs a long rest, combined with professional help.