It would have helped if you wouls have stated what kind of document this appeared on.
Company G, 62nd Pioneer Infantry
Discharge on the date stated. The reason was DEMOBILIZATION. The Army was being reduced to peacetime levels which were extremely low. The Army started discharging the 2 million men that never went to Europe within 30 days of Nov. 11, 1918. The date of this discharge suggests that he may have had to wait to be shipped home from overseas before he was discharged.
He appears to be being admitted to a veteran's care facility because he has some kind of pulmanary (lung) problem as well as ailments numbered 1711 and 1712. I doubt that whatever they were would still be called by the same names today. If he was gassed that would explain the lung problem.
He may have been recieving a disability pension.
The date at the bottom is roughly 5 years after discharge which suggests that he may have been a casualty that never recovered his health.
There is a certain amount of speculation in my answer andonly getting this man's documents can reveal the precise story.