If the parent has any knowledge of mathematics at all I can't see why they would use Saxon.
To learn mathematics endless repetition can be stultifying.
The goal should be to develop understanding and technique. Both were really lacking in the schooling I was given.
When principles are understood and technique is properly executed everything is 10 times simpler.
And that's what you want.
You don't want to create a distaste for the subject by forcing mindless practice.
Until quite recently in human history, the best way to really learn something was considered to be constant practice. The attitude that nothing should be hard work or boring or "distasteful" is, I think, the primary reason people are getting progressively more ignorant. Individual people have been trained to think that anything monotonous is beneath them and so they learn the basics and then lose the skill due to non-use.
Why does the Church use the same old liturgy year after year? Why isn't the Novus Ordo, with its entertaining aspects and different readings over a three year period a panacea for building the faith? Because the faith isn't constantly practiced day after day, year after year.
Many things can fun while learning. The multiplication tables are not generally considered to be one of those things. But they are a foundation which has to be constantly reinforced to really learn other things better. Of course, even multiplication has a foundation--addition. So many people I meet haven't really a clue how to or why these skills are necessary. They can, of course, work out an addition problem if a real need comes up and they really do understand how to do it, but they are not proficient at it and are utterly unable to do such simple tasks as giving change.
A few years ago I was at a fast-food restaurant. The bill came to less than $10.00. I handed the kid a $20.00 bill. He pushed the buttons on the register, but pushed to two and then the double zero twice. The register told him to give me a little over $190 in change. He put the twenty on the register and started to count out the change...and after he had three twenties in his hand, he stopped and put them back. He looked at the total and you could see the steam flowing out of his ears and eyes as his brain was overheating. He knew something
was wrong but couldn't figure out what it was. He stopped the manager and explained that it looked like there was a problem and he was sure that the amount the register told him to give me was too much. The manager showed him how to count change and this kids was awe-struck. He knew how to count. He knew how to add. And, I daresay, he understood the "basics". But he was utterly unable to put those skills to use. These kinds of anecdotes can probably be multiplied exponentially by many people.
On the specific question of Saxon Math, I did not start using Saxon for my children until the fourth grade so I can't say from experience whether or not Saxon Math for a first grader is a good program. But if it is similar to later grades, then it is a fine text for teaching math.
Furthermore, the comment than a parent who has "any knowledge of mathematics at all" wouldn't need to use Saxon is plain ignorant. What makes homeschooling possible really isn't the knowledge of the parent, per se, but the fact that the tools (i.e., ready made text books and other materials) are available to homeschooling parents so they don't have to make a full-time job of creating all the material needed from scratch. Many homeschooling parents have other children and households to maintain at the same time they are working with a child.