I wonder if anyone could help me with a translation of this example from Lexitron dictionary:

ผมลุ้นจนทอดถอนหายใจ เพื่อให้เขามีทางได้ทำความฝันให้เป็นจริง

(NECTEC Lexitron 2 TH-EN)

I can piece it together about this far:

"I support him until....?.....a deep sigh in order to benefit him and make his dreams come true."

but the first clause makes little sense. Is จนทอดถอนหายใจ idiomatic, and if so what does it mean?

Thanks in advance

ขอบคุณล่วงหน้านะครับ

ทอดถอนหายใจ - to take a deep breath and sigh.

ผมลุ้นจนทอดถอนหายใจ can change to a simple saying "ผมลุ้นจนเหนื่อย".

When you have to push, to encourage or to support someone a lot, you might feel exhausted or tired that cause you take a deep breath and sigh from doing so.

Thanks yoot!