Greetings. First, you can modify child support through the child support enforcement agency for free (or very low cost).
My suggestion is that you start to demand that she place the child in approved daycare. The other option is to ask her how much she wants and pay that amount (or close to it) by agreement - as long as you have it in writing - court order or modified agreement). Have the order read that you will pay X amount, including day care, as long as the child is enrolled and attends on a daily basis, but will pay XY amount if the child is not attending the said daycare or another which you approve of in writing prior to enrollment. If you pay directly to the provider, you pay more support, since she likely gets the tax deduction.
Specifically to your questions:
Yes, you may be held liable for the court, since Grandma does deserve some funds for watching the child, but it is unlikely in my opinion. Agree now to send grandma some money in a letter marked negotiations.
You can, but I do not advise this for the tax reasons I raised above.
Janet L. Fritts
Attorney with Rosen Divorce
4101 Lake Boone Trail, Suite 500
Raleigh, North Carolina 27607
919.787.6668 main phone
919.256.1665 direct fax
10925 David Taylor Drive, Suite 100
Charlotte, North Carolina 28262
704.644.2831 main voice
704.307.4595 main fax
The response posted above is based upon the limited factual information made available and is not intended as a full and complete response to the question. The only reliable manner to obtain complete and adequate legal advice is to consult with an attorney, fully explain your situation, and allow the attorney sufficient opportunity to research the applicable law and facts required to render an accurate opinion. The basic information provided above is intended as a public service but a full discussion with an attorney should be undertaken before taking any action.