Is mum responsible for payment of bill

OnlyMe123_2

Looking at this from a different angle, according to the British Lung Foundation, Cancer Research UK et al, the general consensus is that:

"The concentrator costs about 2 pence an hour to run, and the NHS pays these costs. The supply company will arrange the reimbursement of any electricity you use for your oxygen therapy." (from cancer research uk website)

So if the above applies in this case and the oxygen therapy accounted for a large proportion of the usage, there should be funds available to clear the majority of the electricity debt.