Patricia Ruzycki Stirling said the news brought some relief from the anxiety that has plagued her family for months, but the tight-knit clan won't celebrate until Paul Ruzycki is back on Canadian soil.
When he does arrive, however, his entire hometown will welcome him back with a massive party, she said.
Stirling spoke to her brother Wednesday morning once word spread that there had been a major development in the case.
"All he said was, 'We've been on this roller-coaster before,'" she told The Canadian Press.
"He said, 'Things look good but please don't get all your hopes up until I call you and say I've signed my papers and we're headed to the airport,'" she said.
Ruzycki, of Port Colborne, Ont., and Alexandre Paul of Montreal were among 30 Greenpeace activists jailed after being arrested during a protest at a Russian oil rig in the Arctic.
The group will likely be covered by the amnesty bill, but it's still unclear whether some Greenpeace members could face new charges.
The activists, who spent two months in jail before they were granted bail, were initially accused of piracy but authorities later changed that charge to hooliganism.
A spokesman for Greenpeace said the organization's lawyers have no doubt the group will be eligible for amnesty, but it could take weeks or longer to wade through the red tape involved.
The amnesty will go into effect as soon as the bill is published in the government newspaper, which is expected to happen on Thursday. But it allows authorities a six-month period to carry it out, meaning some of the prisoners could wait weeks or months before getting released.
And in order to leave Russia, those who are pardoned must obtain exit visas, which could prove complicated since the Greenpeace crew didn't have visas to enter the country, said Greenpeace spokesman Diego Creimer.
In his 25-year career with the organization — which has seen him arrested in the U.S. for blocking the launch of a nuclear submarine — Ruzycki has never faced such an aggressive response, his sister said.
"The isolation, the solitary confinement, the mental mind games that went on when they were in Murmansk, the deprivation of sleep — things like that — made all of us sick to our stomachs," Stirling said.
But far from dampening his spirit, the experience will only strengthen his commitment to the cause, she said.
"I don't think you'll see any of the Greenpeace Arctic 30 resign as they get out of this situation, I think you'll just see them stronger," she said.
Paul's mother, Nicole Paul, said the ordeal hasn't deterred her son either, though he may give Russia a wide berth on future Greenpeace missions.
"He's looking forward to going back to his normal life," she said.