Conditionality under Universal Credit

I still don't really understand this properly, so will give a real life example and hopefully that will help me to understand it.

Couple, no children, at the moment they claim no means-tested Benefits.

He works 24 hours at slightly over minimum wage.

She works 35 hours at minimum wage and claims low-rate care and mobility Disability Living Allowance.

What would happen under Universal Credit if a) he lost his job and b) she lost her job? Would they be able to claim any Benfits?

Thanks.

(Edited to add) What would be the conditions in doing so?