Not only can you bless someone (ie, pray for them), but we should pray for all people we know or hear about who are in need, and even the entire world.
“Every person is obligated to say, ‘The entire world was created for me’” (Sanhedrin 37a). “Consequently…I must constantly look into and consider ways to make the world better; to provide what is missing and to pray on [the world’s] behalf” (Likutey Moharan I, 5:1).