I am developing a new theory about parental sanity. I am coming to the conclusion that in any relationship there is only so much sanity that can be allocated out amongst all the parents involved.
For example, my beloved Ma is pretty grounded at the moment - normally if contrasted to the rest of the population she is probably up there in the upper quartile in the eccentricity stakes.
On the other hand, in all the time that I have known her, B's mother, Kate, has been the saner of the two. However, as Ma has become more attached to the real world, Kate has gradually become more detached.
She has started displaying extremes of traditional parental behaviour - for example, being unable to finish a phone call even when you have stated, clearly and emphatically that a) you are in the middle of something important, b) your call-waiting is going, c) there's someone at the door or even d) the house is on fire; Wanting me to solve some minor and inexplicable IT issue every time we pop in for a cup of tea; Re-writing history in her head to justify not having done stuff that we had all agreed she would do. The last one is particularly frustrating while we've been working with her.
I am indescribably relieved that Ma has come back down to earth - it is now possible to have a conversation with her like a normal person - communication takes place. Yay!
But is there a quotient for how much madder Kate is going to get in proportion to Ma's sanity? And is it better to have one sane and one mad mother/mother-in-law, or is better that they are both equally just slightly dotty?