I'm not sure what you want, but I made a MouseMove event for a TextBox and put some code in the Userform_MouseMove event to call that TextBox1_MouseMove event even if the TextBox.Enabled is False.
Private Sub TextBox1_MouseMove(ByVal Button As Integer, ByVal Shift As Integer, ByVal x As Single, ByVal y As Single)
Me.Caption = x & ":" & y
End Sub
Private Sub UserForm_MouseMove(ByVal Button As Integer, ByVal Shift As Integer, ByVal x As Single, ByVal y As Single)
With TextBox1
If Not .Enabled Then
If .Left < x And x < .Left + .Width Then
If .Top < y And y < .Top + .Height Then
Call TextBox1_MouseMove(Button, Shift, x - .Left, y - .Top)
End If
End If
End If
End With
End Sub
This assumes that the TextBox is directly in the Userform and not inside a Frame or Multi-page.