Another Solution(Duo): "He used to drink to forget the pain."
why is it not ele bebeu para esqeucer a dor? would that imply that he only drank once, where as bebia is he drank continually/over a period of time, but has now stopped? or is it yet something else?
The imperfect is used with habitual actions. He regularly drank to forget the pain. If you use "bebeu", it would be referring to one particular time, like "The night his wife left him, he drank to forget the pain."
a noite em que sua esposa o deixou, bebeu para esquecer o dor...e então ele bebia todas as noites depois!
It rejected "he was drinking in order to forget the pain", correcting the verb to "drank". Reported 4 October 2018.