Given a travel related situation, and given a specific question about the situation, summarize the question into a title

I'm an American citizen living in the UK. My 7 month old son was born with a collapsed lung and sustained an injury to his lung as a result. He's been given clearance to travel by boat but not to fly as flying could prove deadly. 

I'm on a visa currently. Moving back to the States in March but have been denied by cruise line for him to travel due to his age and lung issue. He is not cleared to fly by plane either. WHAT CAN I DO? It's not an option to extend my visa. I'm more than willing to wait until he's of age to travel by boat which is 12 months but as I said, they said they won't take him. 
Can I ask the US embassy to help me? 

Too ill to fly, visa ending, Cruise line also refusing - what can I do?