Advice on going aboard

Good morning
I am desperate for some advice and will appreciate any help.
My children’s father is refusing to give me permission to take our daughter aboard.

I asked him a few weeks ago if I could take our daughter as my brother had died and I couldnt go bury him as I had just had a baby and she was not immunised.in my culture we have different things we do after the burial ( he said he would give his permission and he even informed my daughters Nusery.)

Just to give you context he doesn’t want to be in the last child’s life and has never seen her she is 11weeks now .
He refused to be on birth certificate .I contacted child maintenance and they have contacted him.

He now he won’t give permission Unless I contacted child maintenance and take his name off the case .

I have postpartum depression and it’s really a hard time .I am so overwhelming and his behaviour is making everything worse.

He sees my oldest daughter every other weekend. I can’t ask the court now because it takes a long time and I have to go January.

Can I go for 3weeks without his permission?
Please help.