My dad very quickly developed Alzheimer's. He was fine this summer. This evening, he wrote down and explained to us how my aunt should carry out some bank transactions. He was very lucid and logical. Two minutes later, he got lost and my mom had to show him where his bed is. He is already on medication and seeing a specialist, and my mom is selling his car so he won't drive. It's very odd how only certain parts of his memory regarding location are affected.
Tomorrow, I'm putting signs on all the doors in the house, and posting maps. Any other suggestions?