Hi sensations, glad you are feeling a little better.
Try and take one day at a time and just aim to get through that day as best as possible, just like you prob did when you had your own kids. you don't have to be a supermum.
Foster kids need stability, routines and bounderies are crucial.
Try and get the baby in a routine, my routine for that age is bottle at 7am, breakfast at 8am, then short nap after dressing (usually in buggy on way to school), then out to toddlers or libray followed by early lunch 11.30am. change and put down for long sleep. bottle mid afternoon and then tea about 5pm. Bath, cuddle and bottle and in bed by 7pm.
with the night waking, you have to be strong and break the habit, at 13m they don't need a bottle and can go through the night. It is worth making the necessary changes as you will be fostering for a long time and have many babies and you need to be able to sleep to function, and your other children need their sleep.
I would put him in the other room with his brother, that may settle him anyway. when older babies are in with carers then can be distrubed by the adults.
Have a good bedtime routine and stick to it, making sure he goes in the cot awake and falls to sleep on his own.
Does he have a dummy or comforter?
Try controlled crying, keep nighttime stimulation to a minimum, do not cuddle or feed him, or talk to him in the night, just pat and shush.
If that does not work at all, then take him dwonstairs, still not talking and put him in his pushchair and put the tv on silent,(keep the lights off) hopefully he will be distrated and watch it queitly till he is ready to go back to bed, you can lie on the settee knowing he is safe if you drop off.
If you have to give him a bottle in the night, then make it weaker by an oz each night untill it is almost water, then give water and hopefully he will stop demanding it.Also don't hold him to feed him in the night, feed him in the pushchair.
Make sure you give lots of attention in the day and plenty of cuddles, try not to make him wait for things in the day and always hold and cuddle him while you feed him in the day.
Most of all be confident in your choices and the children will pick up on that and relax with you and trust you know what is best for them.
It is tiring and sometimes overwheming but you will adjust, they are just kids at the end of the day and you are doing a fab job of caring for them.
Be kind to yourself and pat yourself on the back (and get hubby to bring you some chocolate when he comes home tonight).