This does not mean "he drank the wine himself". It is used as emphasis which is why we use "the uncle himself drank the wine" and not "the uncle drank the wine himself'. "Although the uncle did not serve wine to his guests he himself drank wine." (Sounds like an awful host...) How about this: "The Queen herself opened the door.' One would not expect the Queen to be opening doors. (as far as I know.)
IMHO this sentence is grammatically correct but it would be VERY rare for it to be hear or read anywhere, so DL shouls remove it or modify it to conform better to actual soeexh patterns. Otherwise the results could prove to be more counterproductive with those who are learning GR-EN / EN-GR.
I don't imagine for a moment that this would be correct in Greek, but I feel I must point out that in idiomatic Irish English it is perfectly correct (or at least, understood) to say "Himself drank the wine". This would refer to whoever was previously mentioned or understood to be the person in question.