How can I prove this?

[UmpJM]

Let me sum this up...

The rules and case plays clearly state that the coach's desire to substitute the "player being batted for" for the DH is perfectly legal.

This would, in fact, terminate the role of the DH for that team. But, not the player who was fulfilling that role. As a starter, he has left the game once, and has one re-entry remaining.

The player being batted for is also a starter and has not yet left the game.

Everyone but SAUmp agrees with this.

If that doesn't prove it, I don't know what does.

JM