The company controlled by the family of the White House adviser Jared Kushner is close to receiving a bailout of its financially troubled flagship building by a company with ties to the government of Qatar, according to executives briefed on the deal.

Charles Kushner, head of the Kushner Companies, is in advanced talks with Brookfield Properties over a partnership to take control of the 41-story aluminum-clad tower 666 Fifth Avenue in Midtown, according to two real estate executives who have been briefed on the pending deal but are not authorized to discuss it. Brookfield is a publicly traded company, headquartered in Canada, one of whose major investors is the Qatar Investment Authority.

Mr. Kushner and his son Jared, President Trump’s son-in-law and one of his key advisers, bought the office tower, which is between 51st and 52nd Streets, 11 years ago for a record-setting $1.8 billion. But the building today only generates about half its annual mortgage payment, and 30 percent of the 41-story tower is vacant.