SMS messages to "recycled" iPhone numbers still go to the previous owner's iPhone/iDevices

My brother got a non-iPhone phone and the number he got from the phone company was previously used on an iPhone with iMessages enabled. Now when we send him a text message via an iPhone, the number's previous owner gets the messages.

All fixes I read here and on other forums suggest disabling iMessage on the old iPhone/iDevice, turning it on and off, deregistering the old iDevice, etc. All of that would work if we have access to the old iPhone. But we don't. And strangely enough, the previous owner of the phone number does not want to disable it on his side, though he had contacted my brother about getting text messages that aren't for him.

One workaround I found is to disable iMessage on my iPhone if I want to send a text message to my brother. But that is just a crappy way of doing things.

There must be a way to fix this without needing access to the iDevice where the phone number had been used before. Apple can't expect that this would happen only when a person is switching devices. Phone companies reuse numbers and it's just my brother's luck that he got one that had been regisered with an iphone.

Anyone have ideas on how to fix this, other than changing phone numbers (and hoping it's not previously used on an iphone), or bombarding the previous owner with iMessages so he gets annoyed enough to fix it on his side?

Thanks.