'hey dad' is correct and can be used in written English in informal contexts such as emails between family members or private messages.
Example: Hey Dad, I just wanted to let you know I'm thinking about you and hope you're doing well.
Vampire Hunter: Hey, Dad.
Pretty good, huh Dad? Hey Dad, when I grow up I'm gonna be just like you, huh Dad?
Former Hey Dad! star Robert Hughes has been granted leave to appeal against his convictions and jail term on child sex abuse.
"Five minutes later I said, 'Hey Dad,' and I pointed, and I did the hand gestures he does on stage, and he recognized it, and he absolutely cracked up laughing, to the point where he couldn't breathe".
Russell: Hey Dad, Don't know if Mom shared what I wrote, but this week has been really tough, we lost a sailor over the side in the middle of nowhere, and searched intently for two days, we had aircraft, another ship and helos, but to no avail.
The Happy-Father's-Day Moan Hey dad, Happy Father's Day.
She then appeared in two episodes of the fourth season of the Australian sitcom Hey Dad..! in 1990.
"I said, 'Hey Dad, I've been dealing with this for five years now.
Peter described how the boys egged their father on, "hey Dad, tell them boys that story about when you and Gabe and Luke... Hey Dad, tell them boys about that time when Luke almost broke his leg... Hey Dad, remember that time..."...
She made her screen debut in the Australian drama film For Love Alone (1986) and then appeared in the television series Hey Dad..! (1990), Brides of Christ (1991) and Home and Away (1991) and alongside Nicole Kidman and Thandie Newton in the coming-of-age comedy-drama film Flirting (1991).
