Thats a tough one for a Mom, but if they are rejecting you and being negative , you should not have to put up with that. I would try not to care about his lies, because whatever yo do you will be wrong in his eyes.
What about sending them one final text and say that you feel they are very negative towards you etc and that is not respectful to you as a Mom and that that they know where you are when they are ready to treat you with respect and care you love them very much to get in touch with you, until such times you will not be making contact.
How do the funeral go, did he or they cause any issues x