Awww, glad you had a good night, and that he settled eventually. I was wondering how you got on, so thanks for letting us know! He will be right pleased to see you in the morning, and he will get the hang of other people looking after him from time to time! Good idea to introduce a little backup food though, so you can allow others to take care of him now and again. Just remember that no harm will come to him with a short period of separation from you, and that you and your hubby DO need that quality time together, now and again, and a break from the routine of parenting.
The first time is always the hardest, but dont be put off by him crying for you, he was well taken care of and your sister knew how to settle him. Little ones always do that, but a bit of distraction works wonders, especially as they get a bit bigger and get more interested in toys.