Welcome to the site. I did a quick search around the web for AHCC and could only really come up with this from a reputable website -
https://www.mskcc.org/cancer-care/integ … herbs/ahcc
And as far as a reputable source goes, MSKCC is pretty good! I only did some quick googling on AHCC as I had never come across it before, but I did see a ton of website, newspapers and people etc making claims about it's benefits etc. I am not saying they are wrong, but there was a lack of what I would class as credible info available to read on it and that gets my alarm bells ringing if you know what I mean. Please be aware that there are a ton of claims made about a ton of things online and should your mum wish to try a supplement of any type please consult with the doctors and medical team before doing so.
I hope that the MSKCC piece is of interest to you and I hope that your mums chemo goes well also. Please keep on coming back here and let us know how everything goes.
My best wishes to you and your mum,