Constant infections

Hi, my 10 year old son keeps having one kind of infection after another, I am truly at a loss as to what to do. I have been treating my family including him holisticly for his entire life. He has been seen by a homeopathist and others but no success, I hope someone here can help.When he was just a baby he seemed healthy except he would keep having exploding diarrhea well into toddlerhood. The only other thing that seemed off was every time he was put into a car seat he would literally scream bloody murder, until we discovered that a pacifier stopped him from screaming . He has always been and is very content, if asked how he is, he will always response ' I am doing great'. He says his sleep is 'great'. He has 2 states of being 'great' or 'crying for no apparent reason'. He has had ear infections, infantigo,and times when swells of puss just appear on his extremedies, and staph infection. Each time an infection seems to be gone another will appear right on it's heels and it always is worse than the time before. This last ear infection ended up bursting his ear drum, the last infantigo was so bad it wouldn't stop after two weeks as usual. I took him to the hospital the doctor said he had never ever seen it this bad, I let them give him several different high potency antibiotics which still didn't stop it from continuing to spread. Nothing seemed to help until about 1 week ago when I put him on a ketogenic diet. I have no idea if this diet has helped or if it's just coincidence. I believe strongly in Homeopathic remedies I want to find the right one for him, so this vicious cycle will end. I dread the thought of him having another infection and it's severity. Thank you for your time.