Warren Buffett’s Berkshire Hathaway Inc. said John Noel is stepping down as head of its travel-insurance unit because of illness and will be succeeded by Dean Sivley.

Noel, 67, was recently diagnosed with early-stage Lewy Body Disease, a form of dementia, according to a statement Monday from the company. He will remain in an advisory role.

Noel, a pioneer in the travel-coverage industry, joined Berkshire last year when he sold Insure America and MyAssist, a concierge and personal-assistant service, to Buffett’s company. He sold a previous venture to American International Group Inc. in 2006. The policies guard against risks such as lost luggage, missed connecting flights and delays.

“I don’t think you fill John’s shoes,” Sivley said by phone. “I’ve known him for six-and-a-half years and he’s just an exceptional man. He’ll be involved helping me acclimate, having a little bit more time to share his vision.”

Sivley was previously chief executive officer of GroundLink, a service that helps arrange luxury car trips. He said he intends to expand Berkshire Hathaway Travel Protection by pursuing business with corporate clients.

“Predominantly, now it’s more small-business and leisure,” Sivley said. “What we want to be is a full-scale player, so we’ll figure out over time how to get better into the corporate space as well.”

The Travel Protection business has about 320 employees, and that figure is projected to climb to 450 by next year and 700 in 2018, according to Brad Rutta, a spokesman for the unit.

For Berkshire, the moves are part of a push into commercial coverage, which generates premium dollars that Buffett can invest. The company hired four senior AIG executives in 2013 to build the operation. Sivley will report to one of them, Sanjay Godhwani, executive vice president of Berkshire Hathaway Specialty Insurance.

–With assistance from Noah Buhayar in Seattle.