Here is an issue that came up while I was discussing a grammar exercise with my Chinese language partner. My grammar book has an exercise where the solution is "我被他当做(了)自己的儿子。" My language partner said that 他 in this sentence refers to the speaker's 干爹 gāndiē, which some dictionaries translate as "godfather". Some dictionaries translate both 干爹 gāndiē and 教父 jiàofù as "godfather". However, MDBG translates 干爹 as "adoptive father (traditional adoption, i.e. without legal ramifications)".
Is it correct that the person in the sentence "我被他当做(了)自己的儿子。" can only be someone's 干爹?