I observed most of the Home makers will feel that they are not earning anything. They wanted to earn a little amount for their kids (as I am one of those). I feel she can also earn on her own in her free time through her hobbies. Before you take up any business, list your daily schedule. List everything you do each day. List out what things you want to do or what job you can do in your spare time. Definitely you will find at-least 2 to 3 hours each day for this part-time job. If you have a hobby of painting, you can paint on the old articles remodel it and can sell. Doll making, oil paint posters can do good business. Also you can paint on the fabrics which really a fetching business. Now a day people are giving more importance to fashion and trendy, if you are good at fashion designing then fashion designing, embroidery and tailoring/stitching also a nice creative job.
You can also set up a baby sitting service a good service job for home maker. You may use your house for caring the kids. Working parents will leave their small kids and go out for their jobs. When both husband and wife go out for a job they like to leave their kids with someone. Organize a baby sitting centre at your house itself. This is a good way of earning besides being a social service.
Freelance work is a creative work which gets payments for their articles, creative work and projects etc..,
Work as a yoga instructor to train the children in the schools on part-time work basis. Teach whatever you know singing, cooking, yoga, Tuitions, translator etc.,