Raphael's special angel powers include the ability to heal people and lift curses, and therefore he is the patron saint of medicine. Lift curses you say? Yes, here is an abbreviated version of the story that proves it conclusively and beyond a shadow of a doubt:

1) Tobit is an Israelite who has the misfortune of having birds poop in his eyes and blind him

2) Tobit sends his son, Tobias (the one in the painting) to collect a debt in a faraway land called Media (Iran)

3) Raphael disguises himself as a human and travels with Tobias (so far so good, this is the scene in the painting, though there has been no healing yet)

4) When they get to Media, Tobias gets the hots for a beautiful girl named Sara, who he is allowed to marry because she is his cousin (ew). There is only one problem, every time Sara tries to marry someone, the demon of Lust comes and kills the fiancé. This has already happened seven times!

5) Raphael tells Tobias to burn some fish liver, and the smell drives the demon away. Problem solved, his father-in-law fills in the grave he had quite preemptively dug for his son.

6) They go back home with the hot bride and the money, and Raphael cures dad's blindness, reveals himself as an angel, and leaves everyone alone to live happily ever after.