he is not quite all there
- trí nhớ của anh ta kém lắm rồi: his memory fails him
- trông nét mặt anh ta rất buồn: He has got a very sad expression; there is an expression of great sadness on his face; he looks very sad
- sự thất bại day dứt tâm trí anh ta: his failure preyed upon his mind