The brother of a retired U.S. Army Special Forces soldier who vanished after setting sail from North Carolina in November tells Fox News Digital that his "entire family feels he is alive" as he has an extensive military training background. 

Joseph Matthew Johnson, 44, remains missing after leaving the Federal Point Yacht Club marina in Carolina Beach on his boat around Thanksgiving last year, according to police. Authorities in the Azores Islands near Portugal said a vessel registered to him washed up on the small island of São Jorge on June 21, but Johnson was not on board. 

"We all grew up on the water, up here [in Minnesota] and down there [in North Carolina]. He is very familiar with the ocean and the way everything works," his brother Aaron told Fox News Digital on Wednesday. "He has 24 years of military service. He has lots of training, did several tours of duty outside of the county."

"The entire family feels he is still alive," Johnson added, "maybe out there somewhere stuck on an island." 

MISSING NORTH CAROLINA MAN’S BOAT FOUND IN ISLANDS NEAR PORTUGAL 

Joseph Matthew Johnson

Joseph Matthew Johnson has been missing for seven months. (Carolina Beach Police Department via AP)

Johnson served tours in Afghanistan and South America, so his mother, Mary Kay Anderson, believes he has the skills to survive in dangerous conditions and elements. 

Aaron Johnson told Fox News Digital that his brother "did have some minor boat issues before going out," as he stopped by a shop to buy some parts. 

"He could’ve had motor issues on way out or in," Johnson said. "I know this boat, this boat only had a single engine, so if it failed, he wouldn’t have been able to run a second engine." 

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Johnson also said the family remains in contact with the U.S. Coast Guard and "until more is found the search needs to continue." 

"They did an extensive search both in the air and on the sea, and we’re thinking the boat may have slipped through maybe at night," Johnson said, adding that "we feel strongly he is out there." 

Fox News’ Bradford Betz and The Associated Press contributed to this report.