Why are umbilical cord blood/stem cells a possible treatment for autism?

Most ASD (Autistic Spectrum Disorder) treatment approaches today intend to reduce the symptoms of ASD but they do not address the core reasons. This situation leaves many people with autism with significant difficulties. Various factors are currently being investigated regarding their role in the causes of ASD. Among the factors examined are abnormal synaptic function in the brain regions, white matter disorders, and neuritis. High levels of pro-inflammatory cytokines neuritis were found in the cerebrospinal fluid of children with ASD in addition to activation of abnormal neural pathways.
Umbilical cord blood (UCB) has been studied for its contribution to patients with various neurological diseases and has been found to alter brain connections and suppress inflammation. The theory is that UCB/stem cells lower the inflammation that exists in the brain and in other organs in children with autism and thus allow a developmental leap that was not possible before.

Attached is a short video summarizing the above:
* The video is from 2018. Since then, additional and extensive knowledge has been accumulated through research.