Social Security and financial support for sick people unable to work. I am an EU citizen with an Irish Passport.

AFAIK only Spanish citizenship will bestow a full range of potential benefits, of itself simply being an EU citizen will not cut it.

If you are in employment and paying social security payments then you will have the same rights as a Spanish citizen. Sickness benefits are paid in increments. First 3 days no payment, next two weeks then your employer pays up to 60%. Once you have a medical certificate from a Spanish NHS doctor then the state takes over for up to a year.

However, these payments are only made up until you reach the retirement age when the pension takes over. As you are nearly 70 you would get whatever pension that you have paid into through your social security payments. Probably not a lot as you will get a pension from Ireland which you can add to the years for your Spanish pension and the Spanish citizen has to work a minimum of 15 years before getting a pension. To get the full pension you must have worked 36 years.

If you haven't made enough pension contributions due to not having lived or worked in Spain for the minimum period then you can't claim any Spanish state pensions.

As an EU citizen, you can transfer contributions in your home country across to the Spanish system but I doubt this would be doable as you are already over pensionable age and, I assume, already getting an Irish pension.

Your employer should know the ins and outs of this so that, I would suggest, would be your first point of call followed by the INSS in your area.

I know you can claim a Spanish state pension after one to years contribution, I worked 2+1/2 years and receive a pension the amount depends on how much you put into the system and by claiming it you may be able to access the guaranteed minimum this will depend on any UK pension you get.

os I am a UK national 

As a Irish passport holder did you live, work and pay into the Irish Social Security system? If so, you may be able claim some benefits that are exportable to EU countries including Spain. Please see the contents of these links:

https://www.citizensinformation.ie/en/moving-country/moving-abroad/leaving-ireland/leaving-ireland-and-your-social-security-entitlements/

https://www.gov.ie/en/service/cf633a-claiming-benefits-abroad/

You state you are aged 70? Are in receipt of Irish state pension - providing of course you contributed to the Irish Social Security system? If not, these links may be helpful;

https://europa.eu/youreurope/citizens/work/retire-abroad/state-pensions-abroad/index_en.htm

https://www.irishtimes.com/life-and-style/abroad/how-can-i-claim-my-irish-state-pension-from-abroad-1.2994083

Claiming Spanish Social Security benefits. These links may be helpful:

https://ec.europa.eu/social/main.jsp?catId=1129&intPageId=4792&langId=en

https://www.arintass.com/sick-leave-in-spain/

If you haven't already done so, you should speak with the social worker in your health centre. They should be able to assist you with getting all the help Spain may have to offer.