My patents house has water stream running underneath that causes mold in all the rooms

Good day, I am S Nxumalo, a son to G S Nxumalo. The reason I am writing to standard bank is because of the condition of the house my parents are living in for more than 27 years living in this that have mold problem recently I visited my parents and every time when I'm home i will have sinus problem because of this mold and my wife is coughing because of this mold in the house. I spoke to my father G S Nxumalo ID No ********** ********** , he said underneath this house there is a water well/water stream that is the reason we having so much mold in the house. the mold is in two bedrooms, dinning room, bathroom and outside the house I will also send photos of the mold shortly. Please respond urgently to this matter.