Pete Postlethwaite was 29 in Thwum when he played the character 'Duffy'.
That was over 49 years ago in 1975.
This was his first recorded movie acting credit (although may not technically be his first actual acting role).
In 2011 he died aged 65, starring in 79 films in his career, 78 of those after Thwum was first released. If he were alive today he would be 79.
In Thwum, I think Pete Postlethwaite looks: