I've just been on a work trip with a colleague for the first time. We've never really got to know each other very well, despite working in a small-ish organisation. She has a reputation for being unreliable and very disorganised. She's always the last to sign things and has to be reminded several times. When she eventually replies to emails, it's in a rush of unpunctuated text that often doesn't make sense. She ignores / doesn't stick to rules regarding things like booking devices / rooms / other resources - she'll just e.g. take extra supplies without checking who needs them, leaving others short. She'll often take up a 'cause' - usually something social justice-y that she feels strongly about - tackle it in a cack-handed manner, and then not seem to understand why others don't fall in behind her. She has aspirations to a leadership role, but there is no way on earth people would choose to follow her as she is so disorganised, her behaviour often comes across as selfish, ignorant, inconsiderate of others needs.
While we were away she told me that her son (16) is being tested for ADHD, and that having listened to / read some of his reports, she's fairly sure that she too has ADHD. But she's not interested in getting assessed herself. TBF she is in her late 50s, so not all that far off retirement.
So I'm wondering if I should start cutting her more slack at work or even standing up for her when people complain? My understanding is that if she does have ADHD then some of these things she won't necessarily be able to help doing. We don't work directly together, but people who do are very down on her as she causes them so much extra work by being disorganised and unreliable. But if she doesn't have a diagnosis, why should they take my concerns seriously?