Certain verbs cannot be used with the progressive or continuous form in English and "believe" is one of them. In French, the imperfect works, but in English you either believe or you don't. "He has believed his father." is a translation that works from the passé composé form and not from the imperfect. https://www.thoughtco.com/advanced-french-past-tenses-1368804
Sometimes Duo allows translation of some sentences in the «passé imperfect tense» (like this one) into the English simple past tense. "He was believing his father" (English imperfect tense) is a bit stiff in English and would get a big larf in a pub. I now think it is to do with english not using continuious tenses with stative verbes (like to believe).
Because the auxiliar verb "did" must be used in negative phrases, like "he did not believe his father"; or in interrogative phrases, like "Did he believe his father"? You must not use "did", as auxiliar verb, in affirmative phrases, except when "did" comes main verb, like "He did it". For that reason, "he did believe his father" is incorrect.
In English you either believe or you don't. You can learn to trust someone over time, but the belief is a state of your mind. We use the simple past for verbs like this. https://www.englishclub.com/grammar/verbs-continuous-meaning.htm
Well that would be a bad expectation, because the verb tenses do not necessarily have a one-to-one correspondence in how they are used. In French they do use the imperfect with this verb, but in English we do not use the progressive form with this particular verb. In the present, we use our present progressive much more often then they do so their simple present often is used when we would use our continuous. With certain verbs we do not use the progressive tense and we will use the simple past for this verb when they are using the imperfect. https://www.englishclub.com/grammar/verbs-continuous-meaning.htm
In French, they prefer to use the imperfect with "croyer" because there is often no clear beginning or end. So our two languages views on these verbs are totally different.
can I not say '' he trusted his father" or is this like he told his kid that the sky rains tacos, and the kid belived him. like is it not for trusted like the father told his kid its ok to go sking without anybody with you, but he lied. like is it bluffing or lying or neither or both?