The last clause of Ezechiel 18,10 is as follows:וְעָשָׂה אָח מֵאַחַד מֵאֵֽלֶּה׃ .
There are questions about the validity of אָח in the text, along with questions of how to translate it. According to the entry in the BDB dictionary (and also in the Baumgartner/German dictionary), it is considered to be a textual error and should be seen as an interjection (translated “ah”). The BHS also has a text critical note, indicating the problems surrounding this word.
However, there is another possible explanation for אח :אח might refer not to the interjection, “ah”, but to the noun, “brother,” which has the same form. A noun form in the middle of a series of clauses listing actions of a righteous person is more logical than an interjection in the middle of a clause. A possible translation would then be that of the NASB, which is as follows: ‘and who does any of these things to a brother.” This explanation is further justified by recognizing that the noun form of אח could also be seen as having a similar function to אש, which appears to be a possibility raised by Gesenius’ Grammar.
This second explanation does not in any way answer the question of whether the inclusion of אח in the text is a textual error. This alternative explanation does not remove the confusion surrounding it. Nonetheless, if one wants to take seriously the text as we now have it, one should look for the most logical explanation for the presence of אח, without dismissing it too quickly as a textual error.