hi dere . most likely Mr Das is having behavioural and psychological symptoms of Dementia. It is because of marked loss of recent and immediate memory he is finding it difficult to remember his meals or meeting ppl in recent past. Usually there is disturbance of sleep as well. he will remember very old things of his past in much better detail but recent events he will not be able to recall. he is required to visit a psychiatrist not just for medical treatment but also for behavioural management of these problems. I hope this helps u but feel free to consult again....thank you.