I broke a bone in my hand in 2014. I (eventually, 2 weeks later, I'm an idiot) had it x-rayed, the fracture clinic confirmed that my third metacarpal was broken, and told me to keep the support-brace on it for six weeks, and avoid over-using it. I wrote my risk assessment, and people stuck to it, because it was visibly obvious that my hand was strapped. With our brain injuries, nobody can 'see' that we're damaged. (Thank heavens, if people could see the argument I had with myself about my boots being 'too clean', they'd give me a very wide berth.) People 'forget' that we've had major surgery, or life-changing events, and assume we're 'better', or 'back to normal.'
There's no 'linear' with brain injuries, no fixed time-line, and the advice/support we're able to access varies wildly depending where we are, or how hard we research, and self-source. (With brain injuries...)
My personal experience was that nobody on the 'medical' side communicated with anyone on the 'employment' side, and it all ended up going a bit bosoms-skyward, because I was still trying to do what I did before. (Nobody does it better, etc.)
QI 'Nobody Knows!' klaxon, because nobody does know how much of our previous functionality we'll retain. I was in with my waffly GP this morning, and, when he wanted to put 'stress related disorder' on my unfit-for-work note, I had to ask him not to, because that's effectively medical code for "We don't know." We don't. (Less coherent and articulate than usual today due to GP appointment, neuro-typical people don't have to factor that in.) We don't get a fixed 'no heavy lifting', or 'avoid orange socks' guide-line, and we don't get any time-line at all, because no bugger really knows how brains work/repair.
As you said, many questions, no answers, I'm superficially functional for part of the day, but not as much as 'before', and it's an effort to produce that superficial functionality a lot of the time. (Minger warning, I hadn't washed for 3 days prior to the doctor's appointment, because I knew I needed to preserve my energy/capability for the Spanish Inquisition about why I still wasn't 'better'.)
The testimonies that we're seeing here, that some people return-and-fail, and the neuro-teams say "Yes, that happens sometimes." are a cause for concern. How to address, headwayuk?