"Dad was at every single one of my games in Australia last year, but coming down with terminal cancer this year; he didn't get the opportunity to come to any games this year.
"Being able to come back home to Christchurch and play in front of him is huge for me. It'll be a huge motivation for me this weekend."
The 23-year-old earns his second start for the Kiwis in as many weeks for Saturday's game, after scoring his first try for the side in their win over Great Britain in Auckland last week.
While he's in town on Kiwis duty, Isaako has made sure to split his time between work and family, and has been spending as much time as possible with his father.
"We had a bit of down time on Monday and I got down to the hospital and sat next to him while he was doing his chemo," Isaako said.
"We've got a bit of down time [on Thursday] so I'll probably spend some time with him and take him out for the day. I'm trying to spend as much time as I can with him while being back home."
The Kiwis will take on Great Britain in the back end of a double-header on Saturday, with Fiji taking on Papua New Guinea in the opening match.