Why did Teddy become unhappy when he was put in foster care with a friend? She will be unhappy when she comes back with a female VIP of her own age! I'm sorry about that!
Yes, you should get on well with it from the beginning, just like a child in a strange place will be a little nervous and miss his family. Don't scold him loudly at first, hug him more and talk to him. Teddy, who is over 1 year-old, should have developed the habit of going to a designated place or going out to relieve himself. What are his habits? Ask your friends.