Is this from mold?

15 years ago, when our son was about 2 1/2, we sold our home and moved to a temporary rental which had a bad mold problem. My son had only vomited once in his short life; however, after living in the rental only a short time, our son began having weekly (or 2x/week) vomiting and headache outbursts, usually in the middle of the night. He would cry and cry for hours and then after a long nap, it would subside, only to return the following week (or a few days later). We lived in the rental unit for nine long months and this happened throughout our stay, more at the beginning, less toward the end. The only thing we could attribute it to was the mold. The bathroom walls would “weep” during a rainstorm, and there was mold in the basement and most likely in the walls. After we moved, the next outburst happened about one year later. It seemed to taper off but not for good. He will, several times a year, just out of the blue have to stay home from school because of either a severe headache and/or stomach/vomiting. Could this be due to the mold when he was young? If so, what should we do? If not, do you have any suggestions? Thank you in advance for your reply.