Hello Talk2Her,
I would like to welcome you here, I am so sorry to hear that you are struggling with the pain you feel from your daughter’s words and that she disrespects you in front of your grandchildren. How heartbreaking that must be for you
It sounds like you need to put some healthy boundaries in place, bearing in mind that boundaries are for your own protection. We have a section on boundaries to the right

Under TOOLS, 5th one down, Communicate Boundaries & Limits
You say that your adult daughter and her two children plus your handicapped 65 year old nephew to whom you are the caregiver all live with you, you certainly have a lot on your plate. Do you have any support in place? Do you receive any help in looking after your nephew?
Talk2Her, you say that you want to learn the DBT skill set for communication, you will find those skills here. Along with boundaries which I previously pointed you to, you will find validation tools, S.E.T. and other valuable tools to the right

You will also find reading and posting in other members’ threads to be a great source of help and support. I look forward to hearing more from you x