As a temporary workaround can you set it up with your device, then switch the account it is signed into for music? See the Manage Music & Podcasts section of Change settings for HomePod - Apple Support. Try signing out of your Apple ID there, then have him sign in with his. If the setting in the Home app is to allow speaker access by anyone on the same network then either of you should be able to AirPlay to it, and he would have access to his purchase history, and iCloud Music library if he has Apple Music or iTunes Match.
tt2
Are both devices running iTunes 11.2.6? Does your house have more than one accessible Wi-Fi network that his device can access? It would be an issue, for example, if his device were configured to use the guest wi-fi account on a router while yours used the main channel.
tt2
No, we don’t have a Guest network and both phones are running on our normal BT wifi. Both of us have 11.2.6. I’m gutted, it was a birthday gift and iits been a disaster.
HomePod only with iPhone 6s and not iPhone SE
