Seems fishy to me when he says "I just sent ETH to the contract to get WETH" because this is assuredly not how it works.

You have to call the `deposit` function of the smart contract (transfering ETH with it indeed).

And to withdraw your WETH as ETH, you call `withdraw`.

These calls can be made from here (power user interface! not recommended - use Uniswap instead): https://etherscan.io/address/0xc02aaa39b223fe8d0a0e5c4f27ead...

The source code of the contract is here: https://etherscan.io/address/0xc02aaa39b223fe8d0a0e5c4f27ead...