Candida in the stomach

My dad is giving me a hard time at the moment, I told him that bacteria can invade the stomach if my son is taking ranitidine which is zantac and I ran it by my paediatrician and he saids that candida can invade the stomach if he has low stomach acid. My dad has now become an expert on hospital cameras and informs me that surely if my son has got a bad bacterial infection in the stomach such as candida then a hospital camera inserted through the mouth would see it and I don't have the answer for him and he is making me feel very silly at the moment. I can't find any information on the internet as to whether a camera can see candida in the stomach if it has low stomach acid or whether they can tell if there is an infection in the stomach from sibo. Anyway my paediatrician is doing blood tests on my son to see if he has an infection of some sorts as he is not himself to see if it has spread through his body, he is not capable of doing a breath test due to his disability.