At the moment no. Your only way, would be to find someone very trusted to proxy it for you. In other words, you give them $x, to cover all the fees, + the amount you want to donate, they then send it to Matthew via an acceptable method of donation. Or you could wait a while, hopefully theres another PayPal proxy service starting up very soon!
According to FireZ, the service might come back in a month or so. For now, as malakadang said, is getting someone trusted to proxy the payment for you.
At the moment I don't even have Paypal, and if I did, I wouldn't be able to proxy it as I don't live in US and closest WU is faaar away. Sorry, you should probably post in Community requesting someone trusted.
No you cannot use Paypal. Just mail it, it's safe and if your trying to hide it from your parents they won't know as you won't get a reply letter back.
What I did was get a trusted gold buyer to send the money on my behalf and give him my RSGP, a conversion rate of about .40 cents per mill; it is pricey but if you have no other alternative, it's the best chance you have.
Hopefully Paypal will return soon. Have $25 waiting then I'll upgrade to $100 when I can get another job.