Are you referring to the iPad going to sleep? If so I find just moving the mouse wakes mine up.How did you prevent the mouse from going to sleep? I can connect my Magic Mouse 2 and it works OK until I pause for a minute or longer. Then it requires a tap on the mouse to get it working again. Unfortunately, even though the pointer is not visible, the click registers with unpredictable results. This is very annoying.
In the Pointer Style option it allows you to adjust the time before the mouse/pointer disappears.