Buyer agent wants to lie on offer about down amount

I want to put an offer on my first single family home. I have $15,000 to put down. My buyer’s agent wants me in my offer to say I’m putting $30,000 down instead because it makes me “look stronger”.

I don’t have $30,000 liquid, I have $15,000 liquid. He says everyone lies about this on offers, the seller will never find out, and the purchase agreement is not a financial document.

Is this normal and legal to lie on an offer? Why does the seller even need to know how much I’m putting down as long as the overall purchase price is right and I’m qualified and approved for a mortgage in the amount they are asking?

Edit: 80+ of you have successfully conveyed to me that this agent is unscrupulous. The message has been heard loud and clear! Thank you. I will leave this post up in case some other unknowing soul ends up in the same situation and needs to read the answers everyone has provided.