Nephew diagnosed with Animal-Type Melanoma - Confused

Hello. 

My nephew (9 year old) was recently diagnosed with a rare form of melanoma - Animal-type Melanoma. 

We as a family are really confused and over-whelmed. There is hardly any research and very limited known cases worldwide. 

Does anyone have any experience with this type of melanoma and if so, could you share any info such as treatment and likely prognosis? 

Thank you xx