It took 21 years and the invention of the world’s largest social network for a family parted for two decades to reunite.A father located his ex-wife and long-lost son through Facebook, after years of searching using various people finder sites and even a private detective.US airman Don Gibson met Chrissie in her native country, the U.K., more than 20 years ago.They married in 1989 before she gave birth to their son, Craig, now 22.According to Chrisse, Don was turned down for Air Force service until he moved back to the U.S. Chrisse already had two sons from a previous marriage and didn’t want to leave them behind in the U.K. Eventually, Chrisse and Don lost contact with each other.By the time Craig was old enough to search for his dad, his father had left Texas — his last known location — and moved to Oregon.For years, both Craig and Don searched for each other. Don even employed a private detective through Scotland Yard as well as paid several online tracking companies.Craig told The Mirror that since he was 12 years old he used social media sites to track down his father to no avail.Don logged onto Facebook about a month ago and found Craig’s half-brother through whom he found Craig. He sent his long-lost son a message: “Do you know who I am? Would you like to know. Ask whatever you want. Also tell your mum I said hi. I think of you often. Hope you are all well. Hope to hear from you soon.”The two chatted on Skype on June 16, the day before Father’s Day. Now, the family is set to reunite in October when Don moves to the U.K. There’s even talk of Chrisse and Don re-marrying.“I thank my lucky stars for modern technology because without that we wouldn’t be here,” Don told Mirror.