a year and a half ago the 5-year-old was diagnosed with plafltic aneema. his parents reached out to collin's brother, a 27-year-old who lives in vietnam. >> just hoping he's going to do it. he said yes with no problem so we're relieved but wasn't sure if he'd be afraid or have no interest. or, you just don't know. >> collin was adopted by mcfaddens at only 14 months old they've stayed in contact with his birth family. collin's brother was a perfect match. collin is lucky he has a brother. >> there is 10 million people in the national registry. less than 7% are asians so for someone that is asian decent has a chance of finding a match. >> they're telling their story to encourage people to get on their donor registry. >>. >> it took months to sort out the paper work this tralgz transplant will be performed april 18th. lun will get to meet his younger sister arc dopt fld fr china. now collin's brother will be in the bay area in about a month. we're going to hopefully show you the moment when they meet. again coming up at 6:00 i'm live from sfo, abc 7 news. >>