Home 1 week-toddler grief

Well it's been quite a week. Dan, Grace and William seem to be adjusted mostly with the jet lag, I still have a little ways to go but maybe that's just being tired from being a mommy to an instant toddler. William has had some not so good days with the worst one being Wednesday(Grace's birthday). He is grieving the loss of his foster family and it shows in tremendous rages in the late afternoons. I can deal with the tantrums, what is so hard for me is he hits repeatedly in anger and pinches. He was getting into these cycles of hitting over and over and going after Grace aggressively to hit or pinch. He is either a very happy boy or a very sad/angry boy. I have spoken to my SW, a good friend who adopted a 3 yr. old last summer, and my sister who is a speech therapist and works with age 2-5 yr. olds. They all have been a help, but if anyone else has suggestions I'd love to hear them. He has had so much loss. Thursday night we've seen a great improvement and also so far today. I know this will take time and patience. We didn't go into this knowing it would be easy, it is difficult and toddler adoption is an entire different animal than adopting an infant. Please keep us in thought and prayer, Grace is having a very hard time with all of this too.