1. Well on death of your brother his property devolves upon his legal heir which include his widow and children, if any. So if there is any child born out of his marriage your sister in law along with the child with the permission of court can gift this to you . If your SIL alone inherited the property then she can gift this to you without permission of court.
2. Since there is minor she can gift this only with the permission of court . The court can grant the permission of your SIL deposits the money from its transfer in name of the child.
3. Better make a mutual deed of partition