S/he would need to first transfer fiat and exchange it for some cryptocurrency, and then convert that to BTC or any top coin of their choice, then transfer that to coinbase
Alternative op could explore other exchanges which allows direct PayPal deposit.
You just made it more complicated when you can withdraw the money from paypal if paypal doesn't support trading your money to bitcoin. I hope that coinbase have many options to deposit your money to coinbase then you can buy bitcoin anytime you want. I donvt know the op's country but try reading this
https://support.coinbase.com/customer/en/portal/topics/796531-payment-methods/articles. The paypal can be linked into coinbase but you can't link if it's not available in your country.