How does the UK govt function as PM Boris Johnson remains in ICU over COVID-19?

UK's Foreign Secretary Dominic Raab, as the first secretary of state, is currently leading the government as PM Boris Johnson remains in ICU after testing positive for coronavirus. Raab is chairing the government's daily coronavirus meetings. On major national security issues, such as going to war or ordering a nuclear attack, the decision-making power lies with Raab and the Cabinet.