Big difference (imo) from a spike to 'jacking up'.
Any weight training will increase CNS activity, specifically the ANS. I found the study that examined this...while limited there really wasn't enough to say it will mess it up (per se). https://pmc.ncbi.nlm.nih.gov/articles/PMC6805848/
I forgot what supps Josh uses, but one thing actually is supposed to help with insulin resistance.
He has said stuff about type-2, but 'system inflammation'? Thats a result of type-1 (mellitus) due to elevated cytokine production. To my knowledge, that is not a result of type-2
I am just trying to be helpful here, I am a doc, while no endocrinologist this stuff and particularly neuropsychiatric stuff is my bread and butter (cause I am insane and work out

). I say that just so I dont have to be posting 20 pubmed links as I am lazy and currently doing a teaching rotation

It can elevate cortisol quite acutely, it's well documented. So much so that it can cause impaired memory and learning. Which is likely related to cortisols effect on the hippocampus.
https://pmc.ncbi.nlm.nih.gov/articles/PMC8957269/Weight lifting is a hormetic stressor- technically damaging (so are fruits and veggies actually) but the response of the body is beneficial, only if and thats a big if, the allostatic load of the system can get back to allostasis. Heavy weights increase neural drive and recruitment and a higher HPA response because of the intensity.
His system with type 2 has systemic inflammation- its the likely cause of type 2 and most diseases- basically resistance causes oxidative stress and myokine/cytokine responses. The liver struggles to handle the load as well and that leads to all kinds of pro-inflammatory mediators being released into the system. Over time it worsens and beta cells begin to fail from oxidation amongst other things and you get type 2.
https://pubmed.ncbi.nlm.nih.gov/22252015/you generally see higher crp, tnfa and nuclear factor kappa beta activation in type 2.
You are correct on the supplement, I was just fucking about.
What is likely going on here is he is lifting heavy, causing stress to the system which is already in overdrive, cortisol is released to dampen things, he has insulin resistance which cortisol is exacerbating leading to more insulin release then needed hence the fatigue and feeling shitty. There is likely a counter release of glucagon which does some odd shit to the body as well.