A few months after her mother-in-law died, a dog came to her house.

It's just a coincidence. Don't think so much.

It's normal to have a dog at home. After her mother-in-law died, she kept a dog at home, which was a psychological effect. If your mother-in-law had a dog at home before she died, you would feel normal. It's all their own psychological effects.

If there is a dog at home, don't go near it in case it attacks you. If it doesn't mean to attack you, you can find something it can eat and feed it. It may be hungry. See if it has a dog chain or a dog tag, and some will have contact information. If not, you can post its picture in the circle of friends to see if anyone knows it, or contact the stray dog rescue station to pick it up.