That ex-sailor is going to get nowhere. Even if Obama was involved in his criminal case, a president cannot be civilly sued for actions taken while he is in office. (Nixon v Fitzgerald, 1982, clarified by Clinton v Jones, whic allows for civil suits against the president for actions taken before he was president). In other words, the president has absolute immunity against civil lawsuits for official actions.

ETA Obama was likely not involved at all.