if you can find paypal offers on p2p marketplaces (localbitcoins, paxful, this forum) you'll probably pay a big mark-up over exchange prices. if your partner can withdraw the paypal balance to his bank account, he can deposit to an exchange and pay normal prices. that's probably the best way to go.
It all depends on sellers, but most sellers here on forum offer an option 1:1 based on prevv price, and some offers include a premium price so you can get more fiat for your BTC. Regarding withdrawal money from PP to bank account, this is possible in some countries, but should take into account the fact that banks may share that info with tax administrations, and if that money is not coming from some legal source an awkward situation can occur.
Yes but you know what am I afraid of? My partner has no idea of cryptocurrency. Will his paypal play a big role or just a payment and that's all?
If your knowledge is similar to your partner's, buying BTC may be the least of your problems. Have you made a plan for how you will keep safe that BTC, and are you aware of all the risks arising from such an investment?