I'm really worried about my dad. He's 75 and dealing with diabetes and low blood pressure. Recently, he had some intense chest and back pain, and when he was admitted to the hospital, the doctors told us it was pneumonia with a lung infection. He spent six days in the ICU before moving to the IT ward three days ago. Now, the doctors are saying the infection might be back and they think he needs to go back to the ICU. I'm trying to find a specialist who can give us more insight. What could be causing this infection to return, and how can we make sure he's getting the best care?