It would be great if we had someone who works in the mental health field on the forum who could comment on the length of stay and what that might imply. Two months seems like quite a long time to be in an inpatient facility, does that tell us anything?
Was he being medicated while at the other facility, or just receiving counseling?
IF he was being medicated, did he take the medication willingly or did he hide it/ spit it out after it was given?
The period of time is just about long enough to be titrated / stabilised on a medication regime.
The initial transfer may have been triggered by a crisis (complete psychosis / detachment from reality; suicidal thoughts / plans, attempt seems less likely). Addressing this may have been part of the purpose for hospitalisation, or at least the rationale for the move (secure psychiatric beds are expensive and in short supply).
I very much doubt substantive group work or therapy played any part in his time in hospital. Perhaps some one-to-one work, particularly with regards to any immediate crisis, but you can't get very far in counselling someone who is completely psychotic / delusional.
Far more effective (and far more within the remit of secure hospitals) to look at current medication regimes (probably prescribed by a series of doctors over a number of unrelated appointments, leading to inappropriate combinations / patterns of medication that haven't really been thought through); potentially detox; definitely introduce a new / coherent regime; titrate dosage; stabilise; check that the intended results have been secured; return to main jail.
That this is in the US leads me to think it is even less likely that there was any therapeutic work (e.g., Canada, perhaps more likely that there would be some therapeutic work, but it is genuinely hard to imagine what this could possibly be within 2 months and with someone who has a very limited engagement with reality).
Edit: it might be possible to hide medication in main jail; you won't get away with that in a secure psychiatric hospital. If you are hiding it in main jail, there are real questions about where you get rid of it. The obvious thing is to sell it, which is the main reason prisoners divert medication (any kind! Even meds with no apparent recreational value will have a sale value). I cannot imagine for a second that Chris could negotiate prison drug markets. Standard procedure in a prison med queue might involve drinking a specified quantity of water when taking x tablet, then sitting on a chair with your hands under your bum for five minutes afterwards. Particularly if those meds have recreational value, but similar processes are general safety measures. If there's any suspicion that you are not taking your meds, in an institution with any level of supervision / staff capacity, then you are very likely to be monitored - potentially up to and including toilet contents (unlikely unless proper concerns about proper hardcore drugs, but not impossible). Dumping medication is also not straightforward. If you can't negotiate prison drug markets, it's not easy to consistently lose e.g. two varieties of antipsychotic, an antidepressant pill and an oestrogen pill without significant skills at hiding shit.
The other prison workaround is to give meds as liquids. (And to still insist on 'you will consume this' measures, like the sitting on a chair for five minutes with your hands beneath etc). It is obviously much harder to secrete liquids for five minutes than it is to secrete half a pill. (Only real way to get rid of meds then is to upchuck, not impossible, but very hard to consistently do without someone noticing. Second hand thrown-up methadone, for example, has real value in some prisons).