UNREAL 4 - Sleeping animation that triggers and lasts for a random period of time? How?

Hi, i´m new to unreal and i created an AI creature character for my scene, it already have 3 sleeping animations, 1 (sit) 2(sleep) 3 (awake) but i dont understand how i can make it happen, sleeping must trigger after 20 minutes of gameplay and it has to last for a random period of time, maybe between 1 and 3 minutes… If possible it must stop if another character passes by like in real life.

Does some one knows a similar video tutorial? please show a BP image to follow and understand conections.