Rory Kinnear said he hopes priorities change after lockdown as he spoke of the death of his "brave" sister from coronavirus.
"Heroic and continually inspiring" Karina died aged 48, after testing positive for Covid-19 early last week.
She suffered a lack of oxygen at birth, causing severe brain damage, had been left paralysed from the waist down after a life-saving operation on her spine, and was in hospital with chest infections regularly throughout her life.
"But Karina had defied predictions her entire life", Kinnear wrote in the Guardian.
"So it was coronavirus that killed her. It wasn't her 'underlying conditions'…
"No, it was a virulent, aggressive and still only partially understood virus that was responsible."
He wrote in the newspaper: "No-one could describe Karina as weak – she did not have it coming, she was no more disposable than anyone else.
"Her death was not inevitable, does not ease our burden, is not a blessing."
He said the disease "is making the lives of those most in need of our care and compassion even harder, even more fearful.
"And if there is anything that I hope might come from Karina's death, from the tens of thousands of other deaths caused by this disease and its insidious spread, it is that as a country, from government both national and local, we might make our focus the easing of those lives in the future.
"Maybe we might transfer our common sense of purpose … to invest – financially and emotionally and with a similar level of heroism and selflessness – in the lives of those who will continue to need it most."
He added: "It is a sustaining hope for now, at least."