動詞helpはto不定詞・原形不定詞の両方をとりますが、くだけた文体では原形不定詞が多いとされており、この例文でもそれが使われています。

tbd

The verb 'help' takes to-infinitives and bare infinitives but bare infinitives are said to be the most common in casual text; as also used in this example sentence.

兄弟とも「妻と飛行機の両方は養えない」との理由で、生涯独身を通した。

tbd

Because they "could not both support wife and airplane" the two brothers spent their lives as bachelors.

Both brothers said that they couldn't support both a wife and an airplane, so they spent their lives as bachelors.

Saying they could not support both a wife and an airplane, the two brothers therefore spent their lives as bachelors.

The reason both brothers gave for remaining bachelors was that they couldn't support both airplanes and a wife.

両方一度にはできんよ。

tbd

既要马好，又要马不吃草。

You can't have it both ways.

You can't have your cake and eat it too.

両方の展望にはある共通のテーマがある。

tbd

A common theme underlies both perspectives.

両方いいようにはできない。

tbd

You can't have your cake and eat it too.

既要马好，又要马不吃草。

両親と教師の両方が子供を教育する。

tbd

Both parents and teachers educate their children.

彼女は英語とフランス語の両方を教える資格がある。

tbd

She is capable of teaching both English and French.

彼女は英語とドイツ語の両方が話せます。

tbd

她会说英语和德语。

那个女孩会说英语和德语。

She can speak both English and German.

彼らは英語かフランス語かまたはその両方を話す。

tbd

They speak English or French or both.

彼らの両方がその会合に出席したわけではなかった。

tbd

Both of them were not present at the meeting.