Hi N.. I'm so sorry that you are going through this. This must be pretty exhausting and overwhelming. The best book I ever read about helping children sleep on their own were the "Baby Wise" series by the Ezzos. They started quite a bit earlier than 13 months, but the principles in the book are very helpful, regardless of what age your child is. We used many of their suggestions for all four of our children and they were extremely helpful. All four kids were sleeping on their own and through the night around 7-8 weeks. By 12 weeks old, they were sleeping a good 11 hours during the night.
Yes, there were a few nights in there that we had to let them cry it out, and that was extremely hard for us. In the end, however, they adjusted amazingly fast - within 5-7 days or sooner. We have all definitely benefited from their ability to sleep through the night.
One of the biggest factors that helped our children sleep through the night well was having a regular routine and meal times. Their bodies got adjusted to their routines so they knew when it was time to wake up, eat, play, and take naps. That helped a lot. If you get a chance, take a look at the Baby Wise books. I hope they help.
Sincerely,
D.