(CNN) -- James Morrison was hospitalized on Tuesday night with a recurrence of Crohn's disease but after a second successive 66 has taken the halfway lead in the French Open at Le Golf National near Paris.
The 26-year-old has suffered from the debilitating disease, which causes intestinal inflammation, for the past decade and nearly pulled out of the tournament.
But showing incredible resolve, he has a one-shot advantage joint overnight leader Richard Green of Australia after Fridays' play.
Green had moved one clear at 11-under, but a double bogey on the water-protected 18th left the courageous Morrison ahead.
"It's something I've been used to dealing with on a daily basis," he told the official European Tour website.
"I'm feeling a little bit drained, but I play better with that because I don't have expectations
"I feel a bit worse for wear and just stroll through the day."
Morrison's "stroll" comprised of a five-under par back nine of 31 to ignite his round to leave him clear of the field.
England's Mark Foster, who challenged at the BMW International last week, continued his good form to be four shots back in third after shooting a second straight 68.
Graeme Storm, who shared the first round lead on 65 with Green, was undone by a quadruple bogey eight on the last as he found the water twice and carded a 75 to undermine his challenge.
World number four Martin Kaymer of Germany is also way off the pace on two under, one better than former Ryder Cup captain Colin Montgomerie, whose chances of claiming a British Open spot by a high finish look over.
But at least they made the cut as defending champion Miguel Angel Jimenez, American star Bubba Watson and last week's winner Pablo Larrazabal did not survive for the weekend.