He may be interested in devices which can connect to a phone via bluetooth and to amps via standard audio cables. They basically turn any old amp/speakers setup into a wireless streaming one, and they work quite well.
I use something exactly like this product (an old one from monoprice actually I believe). Simply plugs into the back of a 2.1 speaker set I have. Guests at my place love it, they can easily just connect to the Bluetooth and play through speakers. Pretty seamless. Not sure of any quality drop, my speakers aren't the best.
Right, I use a TT-BA08 to plug my cheap cable headphones in (since most new Smarthones ditched the 3.5mm), which connects to another one which is only a sender (and has no volume controls). That sender receives a line-out of a little analog mixer into which a PC and other devices plug in.
This is quite nice, because it allows me to stand up and walk around while the PC continues its audio playback.
I use something exactly like this product (an old one from monoprice actually I believe). Simply plugs into the back of a 2.1 speaker set I have. Guests at my place love it, they can easily just connect to the Bluetooth and play through speakers. Pretty seamless. Not sure of any quality drop, my speakers aren't the best.