I choose not to say anything to him for his benefit.
I refrain from saying anything to him for his sake.
ーI choose not to say anything to him for his benefit.
「彼のために、あえて口出ししない。」
choose not to say anything で「あえて口出ししない」
for his benefit で「彼のため」
ーI refrain from saying anything to him for his sake.
「彼のために、あえて口出ししない。」
refrain from saying anything で「あえて口出ししない」
for his sake で「彼のために」
ご参考まで！
Because it would not be good for him, I intentionally don't meddle in his affairs.
I keep my opinions to myself on purpose, because if I tell them to him, it wouldn't be good for him.
ご質問ありがとうございます。
①
"Because it would not be good for him"＝「彼にとって良くないので」
"I intentionally don't meddle in his affairs."＝「私は彼がすることには口出ししないようにしている。」
②
"I keep my opinions to myself on purpose"＝「私はわざと口出しをしない」
"because if I tell them to him"＝「なぜかというと、もし私が自分の意見を彼に言ったら」
"it wouldn't be good for him."＝「彼にとって良くないから。」
ご参考に！
カナダ 
アメリカ合衆国 
