Experience with Photobiomodulation for Brain Disorders?

My son was diagnosed with Autism Spectrum Disorder some years ago, he's 5 now. Recently he was also diagnosed with ADHD.

I've seen some progress with the therapies he's using, like ABA (Applied behavior analysis) and speech therapy. His main difficulty is in speech and language. The conclusions from his last EEG show that he could be a good candidate for Neurofeedback therapy, but he hasn't started yet because of other difficulties related to sensory processing. I was told he's too young to take medicine to address his ADHD, but that may happen in the future.

I was considering using a Vielight device on him. I understand that the device does not make any claim regarding ASD and ADHD. It seems the main area of research is around Alzheimer's, Parkinson, PTSD, depression and brain injuries. I've read some experiences from people who used this technique with children and had good results. The claim is that the Default Mode Network, where the device acts, is also dysregulated in cases of Autism.

The only reason I'm considering something that may not help at all is the low risk associated. I believe this technique does not have side-effects, but I'm not an expert in the field.

I would like to read about other users experiences with Photobiomodulation. Even if not ASD or ADHD related, but for example Alzheimer's. If any expert is reading, what do you think about Photobiomodulation? I'm not looking specifically for medical advice, but it's hard to talk about this with doctors. Many dismiss techniques which are not proven yet, and they may have good reasons to do so.