I'm not sure this will happen. CA said that he has technicall issues that doesn't allow him to do it.
You're correct that CA has said this feature is unlikely due to technical issues:
In android it might be possible but IOS... They have tough standarts and it won't help him.
While there are many platform differences between Android and iOS, to my knowledge multiplayer gaming is not significantly more difficult to implement on one or the other. My guess is that when CA says there are technical limitations, that it has more to do with how Stardew is built.
Almost all iOS limitations are around how apps can interact with each other and the system, which only concerns on device features rather than anything to do with network connections. For example, that's why modding is possible on Android, but not iOS.