Juvenile Pilocytic Astrocytoma Recurrence - Starting Chemo

Hello - My 3 year old grandson was recently diagnosed with a JPA in December 2018. The surgeon was able to resect what she felt was 100% of the tumor. 10 months later, the MRI show a recurrence of the tumor and his  oncologist wants to immediately put him on a chemo regimen of Carboplatin and Vincristine. We were told that these two drugs are a first line of defense in childhood tumors. They also carry with them the common side effects of chemo, including, in rare cases, hearing loss and possible secondary cancer. This is a benign grade 1 tumor.  Due to the location which is on the brain stem, the oncologist does not want to start immediately to avoid any symptoms of the tumor since its not causing any at this time.  It is pure agony giving my otherwise healthy grandkid a year's worth of chemotherapy. I'd really like to hear from someone who has gone through something similar. I'm interested in hearing from parents/patients that went through this regimen.

Thanks in advance for your comments and any recommendations.