Simon's Mother In Law - yes Simon is married (this is later referenced in 1 Corinthians, that the apostles wives and family traveled with them)
Sick with a fever - of course, couldn't go to synagogue. This was not because of the germ theory of disease. This was because of impurity, uncleanness. Perhaps inability; but even if she had been physically able, she would not allowed to go by the community.
Jesus' response - physical touch. To touch those that society had deemed unclean.
Jesus has contagious purity.
Why did the woman serve?
Because serving is the sign of being a disciple, in the way of Jesus
Her serving is not about her being a woman and therefore being put back in her rightful place.
Though, it is slight about being a woman, because women were not permitted to be disciples of a rabbi. They are not the people to whom you would be expected to look for an example of discipleship. But it is the woman who ends up being the example to which to follow.
How do we know? Because there are only 3 examples in the whole of Mark's Gospel of people who serve.
1) The angels, who serve Jesus in the desert after his temptation.
2) This woman.
3) And Jesus Himself. "The Son of Man did not come into the world to be served, but to serve."
Messianic secret (why does Jesus tell demons to be silent)
Main Idea: The extraordinary kingdom of God is enacted through radical acts of hospitality and restoration.