Welcome! You rock him to sleep? That's a very sweet vision. I bet your Jack is adorable! Be sure to upload some pictures of your little guy. To help with your question, I would not think he would need to be rocked to sleep. When all of my yorkies were at 13 weeks, they would just DROP asleep anywhere after playing...the food bowl, the middle of the floor, upside down, butt hanging off the couch...literally anywhere.
Perhaps you could increase his play time right before bedtime and then he would learn to go to sleep on his own. Then you could have your mommy and Jack holding times at other moments during the evening.
Hope that helps!!