I contacted Lana, our case manager, and assured her that I would be available to take mum out during the afternoon tomorrow, allowing one of the careworkers to get into the house and give it a clean.

I hope to succeed this week where Rachel failed last. The key difference, in which I am putting my trust, is familiarity. Rachel's years in Queensland have coincided with mum's decline into dementia. The unfortunate effect of this appears to be that mum's mental image of Rachel is more tenuous than those of Greg and I. Mum would not open the door to Rachel last week. If the same thing happens to me tomorrow it will be a first, another depressing milestone on a forever descending path.

The bigger question, which I am sure Rachel considers frequently, is whether mum will ever develop or recapture an easy familiarity with her, given time. Or is it too late already? Is Rachel just the first of us to slip into the 'miscellaneous persons' category?

There have been signs. Greg and I have both been treated oddly at times, and Derek's still greater distance has meant that even dad has trouble fitting him into his current wobbly image of the family. I think all we could conclude from Derek's visit this year was that mum was aware that Derek was somehow known to her, or was at least known to the rest of us. What puts fresh doubts in my mind is the ease with which both mum and dad accepted the two new careworkers, Carol and Jennifer, as my 'friends'. And how quick they were to assume that they had a pre-existing acquaintance with them. It suggests that with the right prompting, mum and dad could be led to believe almost anything about anybody. Indeed, mum seems to switch between trust and distrust, anger and affection, with disconcerting rapidity. We're learning to expect the unexpected.