Q: Is sony dr-bt63ex bluetooth headset compatible with my Iphone 5?

bluetooth support a long range of features those are called bluetooth profiles

https://en.wikipedia.org/wiki/Bluetooth_profile

unless it's broken or don't have propper support for the a2dp or ctp profiles then it will work

this is the list of suppported bluetooth profiles on ios

http://support.apple.com/kb/HT3647?viewlocale=en_US&locale=en_US

http://www.mobimega.com/sony-dr-bt63ex-bluetooth-headset.html

According to this website, Soni dr-bt63ex bluetooth headset is compatible with iPhone 4s, therefore I dont see any reason why it shouldnt be compatible with the iPhone 5. If it supports iPhone 4s, it definitely supports iPhone 5. Hope I helped. Cheers