While Bluetooth is undoubtedly convenient, it also sounds like hell. If you have a budding audiophile in your family, a Chromecast Audio or two is all they'll need to bring their existing stereo into the 21st century.
Computer speakers. They still make those? If your graduate is still using earbuds or worse, the speakers in their laptop, the Audioengine A2+ is a great deal for the money. Just plug the speakers into a spare USB port and the sound will be unlike any PC speaker they've heard before.
The $299 Astell & Kern Jr is a dedicated music player that runs rings around the sound quality of any phone you could mention. It's also portable and can act as a USB DAC for improving the sound of a laptop.
The DragonFly family (from left to right, the original DragonFly, DragonFly Black and DragonFly Red) are a series of USB dongles that improve the sound of your grad's mobile devices, starting from $99.
With its snigger-worthy brand name the entry level Schiit Magni 2 Uber headphone amp and Modi 2 Uber digital converter ($99 each) will offer your grad an audiophile-worthy performance for the price of a celebration dinner.