Some general points on the developing dementia front.
To say the obvious, dementia is scary, not just in the symptoms but in loss of control over one's life. Asking someone to get tested for dementia is a bit like asking them to walk into a police station and own up to a crime with a sentence of life imprisonment.
That being so, I think one thing that can make it easier is, if they'll let you (which they may not), to discuss what they'd like to happen as they get older, maybe talking about if they need help with mobility problems, sensory impairments, shakiness, general physical weakness, severe depression or 'other mental problems'. If possible, focus on words like 'independence', 'supporting you' 'your choices' etc.
Some anectotey stuff that might or might not help to show different angles of what you may need to address regarding diagnosis...
Another thing is that what often gets overlooked (including, sadly, by some GPs, who are, like all doctors, trained to 'look for horses not zebras'), there are over a hundred dementias. Obviously some of those are rare hereditary dementias that show earlier in life, but the key thing is that they vary, and even the most common ones (Alzheimer's, vascular dementia, Lewy body dementia are the ones that come to mind) can vary within each type.
A very close friend of mine started developing dementia in her early forties. The GP's instinct was that it was an alcohol problem, but gave up arguing when she said she didn't drink. He should have trusted his gut feeling, but asked himself what other causes might be. Yes, it was me that, a few years later, 'internet diagnosed' it and sent her back to him. She'd got Korsakoff's dementia, a vitamin B1 deficiency, usually in this country caused by alcoholism, but in her case caused by a foreign diet.
So it would be entirely possible for there to be disconnects between what different people think is amiss.
Then, as we all know here, there's co-morbidity. But again, as a neighbour of mine sighed wearily when a group of us were discussing things not being taken seriously by doctors, you're not allowed to have more than one condition. In my case, my doctor looked despairing when the gynaecologist put my mood swings down to my bipolar, because obviously it would be just coincidence if my sudden mood crashes happened to be just before the start of a perimenopausal erratic period. No HRT for me, then.
There are symptoms that can be attributable to more than one condition but the jargon doesn't help. On DLA to PIP migration, I mentioned attentional memory problems. The assessor mentally translated this into 'mild cognitive impairment' i.e. early dementia and the decision I was sent said according to my GP I didn't have MCI. My GP now asks when I have my routine reviews whether I've got any signs of dementia. Aargh!
So dismantling whether something may be a symptom of more than one condition can help or hinder, but if it's portrayed as "Well, it may be that it's something that can't be fixed, in which case what's lost by finding out, but if it can, e.g. drugs to slow the common dementias like alzheimer's and vascular dementia, or various less common ones, would a diagnosis help to see what might be done to slow it down?"
That being so, my dad was extremely difficult to handle and I had to work hard at giving him the impression at all times that everything I was doing, I was doing because he'd insisted on it (even if actually he'd wanted to argue about it). I could do that because I worked my hardest to help him for as long as possible. Even then, it was a strain. Dementia did not bring out the nicer side of him, sadly.
So when I make suggestions, I make them full well knowing that reasoning and discussion just doesn't work with everyone. Sometimes, like Dad, it's about always having to feel you have the final say even if it means your decision is the opposite of what you want, but it enabled you to be seen to defeat the other person.
Sometimes, it's about other things. For me personally, it would be the terror of institutions whereas I kicked myself when Dad suggested going in a care home for not twigging that as someone who'd spent lots of time in hotels, conference centres etc. it would be fine. By contrast, I very, very rarely stay in hotels, but have youth-hostelled and stayed in countless army barracks. If you offered me a place in one of those modern units that combine a student hall of residence with sheltered housing for elders and a care/nursing home, I'd go for it.
Anyway, the shorter version is that you're not alone in finding this stressful, but sometimes there are little ways of making progress.
