Who pays for other peoples sick pay, maternity pay, jobseekers allowance etc?

I was just wondering, who pays for these things? My friend has been laid off from work and is on job seekers allowance (dole) and my other friend commented about it saying 'all us working people are paying for it' but surely hes paid his national insurance and tax, so hes entitled to this? Am abit confused by how the benefits, national insurance and tax works and what it pays for. Thanks