@targanna, I am an adult liver/kidney recipient who had a deceased donor in 2009 at Mayo Clinic in Rochester. I welcome you to Mayo Clinic Connect and I send my love and hugs to your baby brother. You are justified with your fear and your confusion about what to do, and where to find information.
I hope to lend some assistance to your search. The Liver Transplant Department at Mayo Clinic has a section titled, "Liver Transplant for Children". You will find information about pediatric transplantation, as well as a link to the Mayo Clinic Living Donor Program by entering the link that I'm sharing here:
https://www.mayoclinic.org/departments-centers/liver-transplant/children/gnc-20229058

Is your brother a patient at Mayo?