Awaiting father's biopsy results. How to cope with his delirium

My father has been in hospital for almost 2 weeks. He had been having stomach pain, wind, heartburn, indigestion, bloating, loss of weight, loss of appetite, constipation, diarrhoea, dark stools and feelings of nausea and some sickness. He had a CT scan that showed a blockage near the bowel and then underwent a surgical camera procedure. He had issues with his breathing and aspirated fluid and vomit during the procedure and developed pneumonia. We are waiting for his biopsy results but have been told that he had a large mass in his stomach. He was on IV medication and a syringe driver for a week and then they started him on soft foods. He started to become confused and is now hallucinating and I've been told that he has delirium. His inflammatory markers were raised during recent tests, which indicated an infection and he was supposed to have antibiotics but that hasn't happened yet. Due to covid restrictions I haven't been able to visit since last Sunday but have been keeping in touch with him by phone. For the last 3 days he has been convinced that the hospital staff are keeping him hostage and are trying to kill him and he is constantly asking me to go and get him to bring him home. I don't know what to do for the best because I am worried that if I do visit him and them leave him there that that will make him worse but on the other hand I feel guilty for not visiting and I don't know what to say to him when he rings and says all of these things. I try talking to him calmly and try to talk about other things, which works for a while but then it starts again. I'm so worried about him.