The 22-year-old spent six weeks on trial with the Glovers having left Irish football at the tail end of 2012 while he stayed with best friend and Yeovil top scorer Paddy Madden and was only given his first start by Gary Johnson in January.
And, having become a vital cog in Johnson's line-up, Dawson grabbed the opening goal in the 2-1 aggregate victory over Sheffield United on Monday to help Yeovil tee-up a Wembley final with Brentford.
It capped a memorable weekend for the Irish family after older brother Stephen started for Barnsley in their nail-biting clash with Huddersfield on the final day of the npower Championship season.
The midfielder played for 84 minutes as the Tykes stayed up in dramatic fashion which means victory for the Glovers at the home of English football on May 19 would set up a Dawson derby next season.
"It has been brilliant," Dawson said when reflecting on a frantic 36 hours for their family. "I was so nervous for him, it was horrible.
"We were coming back from Sheffield (after Yeovil's first leg defeat) and it was a horrible feeling watching the scores and praying. Thankfully Palace beat Peterborough and Steve stayed up so that was unreal.
"I was delighted for him and he was saying over the phone that now it was my turn. I can't believe it but happily enough we are there.
"Without a doubt this season has been beyond my wildest dreams. I'm thankful to the gaffer for giving me a chance, my first focus was getting in the team and it has just gone from there. It has been unbelievable to be honest.
"I'd love a Dawson derby, but I don't think we can think about that yet - we have the small matter of Wembley first!"