Do as indicated in the following statement:
He is helping his brother.
(Change into passive voice)
Let's first put the object of the active voice 'his brother', as the subject of the passive voice. Then, we will use the auxiliary 'is' to describe the subject's state of being in the passive voice. We always add 'being' when the sentence is in the present continuous tense, and the verb always remains in the past participle form. We use 'by' and the subject of the active voice 'he' as the objective form.
'His brother is being helped by him.' is the correct answer.