Question

let him help his brother into passive voice​

Answer 1

$\huge\underline\red{ǫᴜᴇsᴛɪᴏɴ:-}$

➡ Let him help his brother

$\huge\underline\red{ᴀɴsᴡᴇʀ:-}$

➡ Let his brother be helped by him.