I don't want to appear to be difficult, but I can only say and recommend again that you need to form a trusting relationship with the team of doctors who care for your mother. This site was set up a number of years ago to be a Q&A site to answer generic questions about topics like 'how dialysis works', 'what is meant by an eGFR', 'what are the things that might indicate that dialysis is nigh' ... indeed any issues about the function and practice of dialysis.
It is true that, where the issues raised in regard to a specific problem have had wider implications, I have (always with caution, and always with reference back to the treating team) discussed specific patient problems, but this is by exception and is not the rule.
I sympathise with you - I really do - and about the concerns you have with and for your mother, but to answer your questions about her would require a breadth of intimate understanding of her past history, drug history, clinical status, co-morbidities (other stuff that has gone wrong for her in the past or might impact her present status) ... indeed, information I can never hope to know, no matter how much you think you have 'filled me in' with it.
Again ... and please, as I have made comment in the past ... try to form a relationship - not with some nebulous 'me' over the Internet - but with her treating team. Only they will know the answers to the questions you ask. Only they will know what her characteristic potassium patterns are - or what drugs she might be on that might either influence her potassium levels (and, on the face of it, 5.1 is not a level that I'd be worrying too much about) and/or her speed of post-intervention recovery - for which she might very well have had some sedation given ... but, again, I cannot tell! Only they will know.
So ... please, ask her team.
I am not your correct port of call.
The Internet is not where you should be looking for these kinds of answers.
Nor, I'm afraid, do I accept requests to 'be friends' - for I notice you have made one. I cannot, and do not, acquiesce to 'friend' requests from anyone ... so, you are not alone in being 'refused' ... others have made similar requests in the past. As a result, no slight intended, nor given.