Hi and welcome to the travel insurance group
Unfortunately, it can be more difficult to find reasonably priced travel insurance when you have had a cancer diagnosis. I don't know whether you've had a chance to look through the member's stories thread yet as it's where the majority of recommendations from other forum members are. If not, clicking on the link I've created will take you straight there.
It is best to phone the insurance companies rather than try and do online quotes as sometimes they can refer to the underwriters to see if they would provide cover when an online quote might just give you a straight refusal.
Make sure you have all the information to hand about your mum's diagnosis and treatment before contacting the insurers. This is a list of common questions that insurers might ask when you're applying for insurance. Some insurers might ask for a letter from your mum's doctor to prove that they have given her permission to travel.
I do hope that you can get some reasonably priced travel insurance and that your mum has a great holiday wherever she's planning on going.
"Never regret a day in your life, good days give you happiness, bad days give you experience"
