If you believe you have additional evidence, or if you believe the evidence already submitted (including your own statements) will eventually provide the authorities with enough evidence to substantiate, I would speak to the police again (and possibly again, and again). I would also consider going to the country prosecutor/sheriff and or state DA.
You don't indicate how you know she has been taping phone calls, nor what would be her motivation in saving and transcribing them, but if you have evidence or the husband has evidence of her violating Florida's two consent law, why don't you try letting that be the starting point of getting charges brough against her. Mostly likely, the husband would have to seek to press the charges, as he is the only one who can state of the necessary elements - that he didn't know or consent.
He should also discuss with CPS what evidence they relied on to find substantiation (beyond yoru testimoney that your grandson told you - the detective probably believes that you are motivated by wanting the husband (I assume that is your son?? or no?) to prevail on the issues, including custody, in the divorce and so your own testimony may not be the best you can get. The father can file a Motion with the divorce court to disallow visitation with the mother (and/or put custody in him if it isn't already) and at best, XXXXX XXXXX
Finally, but most importantly, your grandson should probably be in some very reputable counseling/therapy to help him cope with and survive in a healthy fastion from this horrendous abuse - not only does he need it, but it would be hard to believe the allegations of a father or grandparent if they didn't follow up with their allegations by getting the child the much needed psyological care he needs.
Hope this helps to clarify.
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