High ferritin, brain fog and dizzies: MTHFR mutation, No diagnosis yet

My son has been dealing with high ferritin along with brain fog, dizzies, nausea, tingling in hands and feet, insomnia, exhaustion, stomach pain, depression for over nine months. Seen many doctors, done a lot of tests, with no results/a lot of them come back normal. Did find out he has the MTHFR mutation with two variants which he is taking supplements prescribed from his naturopath. Bought products to help stimulate his vagus nerve to see if this would help. A few of his symptoms have improved a little bit. He is not my same son, this is talking such a toll on him and his family including myself. Any suggestions or help would be greatly appreciated. The health care system is so frustrating, to get in takes months, need referrals for everything, only treat symptoms and not try to find out what the root cause is cause is.