To say that somebody does something alone means they do it not in the presence of others.

就是说人孤独而死的意思是,他们死的时候身边没有别人的存在。

youdao

So don't sit there and say, "Somebody should really do something about that someday. " Be that somebody, and make today the day.

所以别在那坐着然后说：“我有一天一定会成为大人物的。” 要成为大人物，现在就开始努力吧！

youdao

To say that somebody does something alone means they do it not in the presence of others.

就是说人孤独而死的意思是,他们死的时候身边没有别人的存在。

耶鲁公开课 - 死亡课程节选

You can say "Why don't you" when you want to suggest that somebody else do something.

当你想建议他人做某事时，你可以说“Why don't you~?”。

Why don't 课堂 - SpeakingMax英语口语达人