can a person catch pneumonia even if he hasn't been around anyone? (secluded on an acreage)?

There are two types of it. One comes by gene. The other is caught when one stays in the same position too long, too much. The liq. builds up in the lungs, and can cause this.  

Pray to God for more help here. 

Yes there's different types of pneumonia out there and not all are community acquired from other people. 

Our bodies are not sterile and we have bacteria present and even fungal spores in the air that can cause pneumonia. Your spit has bacteria that when swallowing is defective one can aspirate saliva down your windpipe and into your lungs causing pneumonia. 

Some bacteria in your throat can be keep in check like strep but when immunocompromised can find their way into your lung and cause pneumonia or even meningitis. These bacteria are called opportunistic bacteria because they normally don't cause disease until your host immunity decreases.