I would avoid doing the transfer by paypal, the fees are high and then you have to wait to get a check from them or for it to be transfered to your card.
Also, a paypal note: I have sent my mom money several times using paypal and she will go into her paypal to get the money transfered to her bank account and every single time, we have done the wait period and it NEVER goes in. She has to log back in and redo it. Seems like they want to hold onto the money for as long as possible. It's just annoying and when she goes back in, she does the same exact thing as she did the first time.
I would suggest moneygram as it is instant and can be picked up in so many places including Walmart. There is a fee but at least it's instant. He could also just go to his bank and do a wire transfer, cost is about 25 pounds or so and takes just a couple of days.
You will have a hard time using Maestro in the states even though they are a Mastercard co. Maestro is a shorter number too. Even US airways doesn't accept it HERE!!!! Had to book my trip through a third party agent to use my Maestro.
If you're traveling to the states, the Post Office offers a money travel card that is free. You can use it anywhere in the states, it's protected if you lose it and you can reload it. Best of all, there are no fees for using it compared to fees that your bank would charge you for your bank issued card.
I think American's coming here with their major credit cards will run into problems using their swipe card here. We were forced to walk away from so many retailers because they refused to swipe our American card and said they only take chip and pin. Yet you could clearly see the machine was capable of swiping a card. If a store was willing to swipe, we knew we would be standing there for 10 mins while they figured it out. I wonder how much money is lost because of this. This was nearly 2 1/2 years ago so I don't know if things have changed but if they accept major credit cards then they should offer swipe and chip/pin options. I hope things have changed on this.