Paul Johnson's family said the 74-year-old disappearance remains a 'mystery'.
Police are appealing for the public's help in tracing the teenager.
The 25-year-old was last seen on Monday and concern is growing.
A young girl who was missing overnight in Glasgow has been found safe and well.
Florence Brooke, 24, was reported missing from the Quarrywood Road area of Glasgow at around 2pm on Tuesday.
Denis Findlay, 74, was last known to be at his home in Buffies Brae, Dunfermline, at around 12.55pm on September 3.
Patryck Lipinski is believed to have travelled from his home in Bathgate, West Lothian, to Ballachulish in the Highlands.
The 15-year-old was missing for more than 24 hours.
Christopher McDonald disappeared in Glasgow on Sunday afternoon.
Justin Tosh was last seen in Aberdeen on Thursday, January 28.
Abbie Macintosh, 16, was last seen on Friday, January 29.
More than 500 people were questioned after James Coyle went missing in November.
Kerys Lynch was last seen leaving her house in Kilwinning in North Ayrshire at around 12.30pm on Monday.
The company intends to create a pork-scented mist called Puperami that will help lure missing dogs out of hiding.
Oliver Dalton, 14, was last seen in the Denny area of Falkirk on Friday afternoon.
Chloe Brand, from Carron in Falkirk, was last seen at around 3.30pm on Friday.
Police are looking to trace Joe McGee, 32, who was released from Greenock prison last year.
Thomas Foley Smith, 29, was last seen at the Cairn Hotel in Edinburgh at around 12pm on Friday.
Merseyside Police have appealed for the public’s help to track down Jordan Goode, 17, and Obakeng Sitole, 15.
Michael Fitzpatrick, 48, was last spotted in the Haugh Street area of Falkirk at around 12pm on Friday, April 17.