As far as I know, MLB allows players to BUY into health insurance each year for life after 1 day of service. But this player was homeless, so I imagine he couldn’t buy much of anything.
No, if you make the 25-man roster, it's $700,000 [1]. The minimum for the 40-man roster is around $80K. This player was signed as a player on the "restricted list" which does not fall into the 40-man roster [2]. They signed him for $0.
He appeared in over 90 games at the Major League level from 2016 to 2018.
You cannot appear in a game without being on the 25 man roster (40 after the late season roster expansion).
I was pointing out the assertion that he was "homeless" during his playing days, which doesn't pass the most basic smell test. For one thing, teams arrange at least temporary housing for rookies and recent call ups.