Yes, my DF, and yes, him being not officially diagnosed is causing a lot of issues now he is in ill health, frail in need of extra care.
He actually discharged himself from hospital after a stroke last summer, without having completed treatment or waited for tests. He then wrote a letter to the hospital consultant, to explain that the hospital environment was difficult for him with his 'particular needs'.
Since then he's refused follow up checks and treatment and wouldn't let my DB shop for him (he probably wouldn't buy the correct brands or the very particularl items he wants) or help him (again, this would disturb the routine), instead he insisted on driving his car to the one shop he can do his shopping from (We later found out he wasn't allowed to drive and the police have now physically removed his licence) and sort of pretended that he was ok.
Until he couldn't cope, but of course he wouldn't tell anyone and because he lives like a recluse it went unnoticed how very bad things had become, until eventually, he became so frail he fell broke his hip. We've then had four months of him being in and out of hospital with influenza, a second hip fracture and then pneumonia. So he is really struggling with having carers now and refuses to do any of the physio therapy or exercises that the OT tries to get him to do.
Some of this would obviously still happen without ND in the mix, but it's made things more complicated as he has created a very isolated and reclusive life for himself. Basically living alone surrounded by his model trains and cars/motorcycles. My DM phoned him regularly to check be he insisted that he was fine. Going over again in a few weeks!