Toddler hates mom

We have found this to be pretty common, because it is common for foster kids to not have any/much of a bond with a father figure before coming into care, but they have a previous bond with mother. So your wife = competition and a threat to the mother-bond that this little boy is mourning right now, and you = an opportunity for something the kid has alway craved, a father-bond. This has been the case in our family with three of our four foster kids.The only answer is perseverance and time. As your wife understands that his reaction is not about her at all, but about his emotional struggle to work through his loss, and as she continues to offer care and love openly despite it, he will find his way through his grieving process and reach the point where he is able to accept her love without feeling threatened by it.Of our three who have struggled with this, two of them developed the closest bond with me in the end, and one has remained most closely attached to my husband, but has developed a good relationship with me, too.