Behavioral change. Phone etc.

My grandmother's behaviors have changed drastically. She has a very weak memory nowadays as well as her behavior has become childlike. For example, she has become possessive about her stuff. Every single day she takes out all her clothes from her wardrobe checks them and keeps them back there. And if she doesn't find something (which Is mostly due to her own weak memory) she throws a tantrum. The other day she put some rice on the table itself and started eating. When was asked why did she do that. She said she thought it was a plate. Her behaviors have been a little out of control these days. However I have noticed that she remembers almost everything about the past. Like names of relatives, dates of marriage etc but forgets things as simple as words like toothbrush, phone etc.