Jess Kent Thomas and Kent David Thomas were sentenced to eight months' jail wholly suspended for 18 months for breaking into a family member's Youngtown unit on Christmas Eve and bashing her partner.

There was a verbal altercation at a Thomas family Christmas function preceding the Youngtown incident, with Kent and Jess going to the unit hours later, kicking the front door in and starting a fight.

Kent walked straight to the bedroom of Colin Corsa, who was asleep moments before the incident and punched him several times.

Mr Corsa was bitten on the left side of his chest by Kent. While the victim fought with Kent, he was punched to the kidneys, head and back by Jess.

Mr Corsa poked Kent in the eye and started pushing Jess away from the bedroom, toward the front door.

Jess threw several punches, as well as biting the middle finger and thumb of Mr Corsa's left hand.

During the fight, Mr Corsa flipped over a banister outside his house, landing on a lawnmower in the front yard.

He stayed on the ground for about 10 seconds because he was winded, before hiding behind a lemon tree in the yard.

Mr Corsa was treated at the Launceston General Hospital for multiple superficial abrasions, bite marks and stitches on his toe.

During sentencing on Monday, Justice Robert Pearce noted the two men were hardworking, had no violent priors and entered guilty pleas before the victim and his partner gave evidence.

Kent, 49, and his 28-year-old son changed their pleas to guilty until after a jury was empanelled and Crown prosecutor John Ransom gave his opening address.

Justice Pearce said a deeply held and long-standing feeling of ill will was held by Kent and Jess toward Mr Corsa.

During sentencing mitigation last week, Jess told the Supreme Court he met Mr Corsa about 15 years ago when his aunt called him for help because her partner was abusing her.

"I do fear for my aunty's safety," he said.

Kent told the court he and Jess regretted what they did.

Justice Pearce said he was satisfied the feelings expressed by Jess and Kent were genuine.

They were also given a 12-month Community Corrections Order, required to report and comply with a probation officer, not leave the state without permission from the court, notify the court of address changes, not commit an imprisonable offence for 18 months from Monday and complete 84 hours community service.