sickness benefits for a child.

Please bear with me, this is very new to me, only ever had to think about t/c &c/b before.

my 4 yr old daughter has lymphoma. both me and hubby work,although my gp has signed me off.
we have 3 other children.
i am feeling a little bewildered by all this and dont really know which way to go, and i dont understand all the different sickness benefits.
what would we be able to claim?
we both earn well over the minimum wage.