Tack Imsdal83 och Storfittan (5+ på det roliga nicket, hehe

) för era fina ord, det värmer.
To Issys/Olivers dad; J is not blaming you per se but she expresses a disdain for people contacting her with accusations towards her abilities about the current situation, and she says that she wishes that "Olivers dad" would actually "step in and try to make a difference for the better" to improve Olivers current distressing/anxiety-inducing situation, sort of. Which is ludicrous as you very well know, you havre obviously done everything in your power to get insight into or improve Olivers situation.
If she really wants you to "step up" and help navigate as an ally towards Olivers wellbeing she could issue a "power of attorney"-document, a fullmakt, or grant you shared custody (which in Sweden does not equal shared physical custody, as in the child living one week with one parent and the other week with parent nr. 2, but refers to the involvement each parents are granted to have in decisions regarding the child as well as permitting access to documentation regarding the child in question).
However, I would advice you to leave her comments be, and regard them as coming from a person not in their right mind - basically take her comments as if they were said by a person of diminished capacity who lacks full insight into the comments made and her own fault in the matter. You know you have no responsibility in the state care decision, you know you have only Olivers wellbeing in mind and are not out for revenge towards J, and you're better off just reaching out to Oliver as a supportive adult who has no ill will for his/her (severly incompetent/challenged) mother. Remember that O has lived with J all his life and that O will likely turn against anyone putting down his (albeit incompetent) mother - so try to stay on O's good side and gain his confidence by not criticizing J right now.
J's statements about you in the latest videos are very non-accusatory compared to things she has said about you in the past so if I were you I would really just leave those comments be.
PS. If you're wondering why I take the liberty of giving you the above advice, it comes from several years of working with teens in state care with complicated relationships to a parent or both. Thread carefully when reaching out to O in this very frail and emotionally rocky situation as O is very vulnerable right now. You have a golden opportunity to form a bond now that he is out of J's imidiate influence - but in order to do so you must choose what you write carefully. That's all.
(also sorry for spelling errors etc, my phone tries to autocorrect each word into swedish constantly and I dont have time to change the settings or proofread my text right now)