Grade 3 brain cancer travel insurance

Hi all, this is the first time I've posted here and I'm looking for some advice. On 4th Sept 17 my husband had part of a brain tumour removed and from Oct 17 to 4th Sept 18, he had radiotherapy and chemo. He still has 30% of the tumour that can't be removed. 

I've been looking for travel insurance with little success; either they won't insurance him or it's at least £1500 for 2 weeks in Spain.  Can anyone recommend a company that might insurance him? 

TIA