It would have been enough if you were still alive.
If only you had not died
こんにちは。
ご質問ありがとうございます。
① "If only you were alive"=「あなたが生きてさえいれば」
② "It would have been enough if you were still alive."=「あなたが生きているだけで十分だった。」
③ "If only you had not died"=「あなたが亡くならなければ」
☆"died"=「死んだ」の代わりに"passed away"=「亡くなった」も使えます。
ご参考になると幸いです。
"If only you were still with us."
"if only”「〜ばよかったのに」
"you" 「貴方」
"were still with us" 「さえ生きていれば」
[さえ](https://eikaiwa.dmm.com/uknow/questions/66757/)についてもっと詳しく知りたい方はクリックしてください。