No. A dependent cannot have a dependent. If you did not have any income from working in 2017 then you are not eligible for any child-related credits like child tax credit or EIC. Not sure why you think filing will prevent a future audit. You file a tax return if you have taxable income. You say you did not work, but you did not say if you had any other income such as unemployment compensation, disability, etc. If you have a 1095A for healthcare you need to file.
If you had less than $4050 of income in 2017 and you lived with your BF the whole year, he could claim you as his dependent. If your son also lived with your BF all year then BF can also claim your son as his dependent. You did not say if your BF is the child's father. If he is not your child's father then he can get the personal exemption of $4050 for your son, which lowers his taxable income, but cannot get any other child-related credits. If BF is also your child's bio-dad then he can file as head of household and get child-related credits.
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