Dependant / de-register / required to fill in a tax form if no longer earning a taxable income

I am married and a registered tax payer, no longer earning a taxable income. Do I need to de-register as a tax payer and if not, do I need to submit a tax return?
Can I add my medical expenses to my husband's tax return as a 'dependant' (we do not contribute to a medical aid scheme)?

Only if he pays for the actual expenses can you include them in his tax return. You do not need to deregister, but you you should submit nil tax returns each year.