No idea which topic is best for this so here I am
My DC (10 years old) came home after seeing his dad at the weekend stating that he doesn't want to get the flu vaccine. He has had the flu vaccine every year since nursery. His dad has never had any issue with DS receiving the flu vaccine.
DC states he doesn't want this because of some story his dad told him. His dad is always looking for ways to upset me and cause me distress so I have no doubt this is the root of his new found 'belief'.
He has emailed school to say that under no circumstances can DC get the flu vaccine. I will be getting the flu vaccine too as I always take it really badly otherwise and end up being off work for several weeks. I also have my partner to think about, my mum who is elderly and my two year old child.
Where do I go with this? Surely as the main carer and with DCs young age I have the final say?
Exp had done similar before to upset me. He emailed my work when he discovered DC had been invited to take part in a promotional video with me and told DC that paedophiles would be watching him and would try to find out where he lived 
I've lost count of the things he has done to get to me. The latest was last week turning up to school to collect DC when he wasn't meant to (also done this previously and refused to return DC to me for the whole weekend despite the interlocutor being in place) and when DC walked home as he wasn't expecting to be collected, exp banged my door and demanded I bring DC to him and then wouldn't leave my property and kept telling me I should be ashamed of myself for letting DC walk home as I didn't know if he was safe or not.
I am sick to death of all this nonsense. It causes me so much distress and anxiety and he knows this. DC believes he shouldn't take the flu vaccine but now feels very stuck in the middle as I wish him to get it and his dad is telling him not to. He became very upset tonight at the dinner table. He now doesn't know what to do
If I tell DC to do as he wishes, chances are we all get flu and need time off work (my partners work is unpaid as no sick pay which puts us in a sticky situation) and exp feels he has 'won' and continues to exert control over me
If I insist the vaccine is done it puts DC in a horrible position. I believe he tries to keep his dad happy a lot of the time. Exp will fight this til the death. He will likely try to ke me to court over this. He tried to take me to court to stop me giving DC haircuts as he wanted to take him to a barber 
Any advice on how the school will deal with this? Thank you for reading this far