From Heart of Mary Women’s Fellowship:
We aren’t shown what happens to Tobias, Sarah, and Raphael on the journey back to Nineveh except for Tobias planning to use the fish gall to help cure his father. But really, most good stories know to show only what is necessary. I think one reason that the way back home is faster for heroes than getting to where they went in the first place is because getting home is a matter of working backwards. And since they took care of all the obstacles that blocked them from getting to their first destination, the path is clear for the way home.
I also look into how Anna and Tobit are doing in the meantime in Part 2:
Impatience and anger are both forms of short-sightedness. While Tobit is assured of Tobias’s safe return in spite of his physical blindness, Anna is equally blind due to her anxiety and impatience. Like Anna, we may not see the blessings in our lives due to our own myopic attitudes. Sometimes, we tend to make the biggest deals out of problems that aren’t actually that big a deal in the long run. Or we can be like Tobit and ignore our problems and pretend that they don’t exist.