Isaako, who spent several weeks by his father's side in hospital in late June and early July, said his dad collapsed one day at work and was sent for tests which revealed cancer in his nose, which then spread to his brain and through his body.
After playing in Samoa's 24-6 win over Papua New Guinea on June 22, Isaako dashed back to Christchurch to support his father.
"At one point, he was only given a few weeks to live when I went back home. It's now been a month and he has managed to do well," Isaako said.
"He is doing his treatment and his chemotherapy and all that soft of stuff is helping him. Hopefully if he can keep doing that, he can keep living.
"He's definitely inspiring me. When I went back home, the club gave me however long I needed and I was planning on staying until I knew he was stable.
"He sat me down and spoke to me and he wanted me to come back to Australia. That's why I came back earlier than expected. He motivates me to keep training and playing and the last two weeks since I've been back it's really shown. I'm getting more confidence knowing my dad is better.
"He was diagnosed in early March, so since finding out about it, the symptoms started to kick in and that's when he got really bad. He is making a lot of progress which is positive signs.
"He is 49, it's his 50th birthday next year so we're hoping he can make it to that."
Taai's condition is a week-by-week proposition and Isaako is dealing with the situation the best way he can.
After representing Samoa for the first time in June, 23-year-old Isaako received the news that shook him to the core.
"I got a call the next morning from my sister saying the doctors had spoken to her and they said dad wouldn't make it past the week. I was bawling my eyes out," Isaako said.
"The first thing I did was call Seibs and said I needed to go home and be with my dad and I booked the flights straight away. I left on the next flight to Christchurch. I was there for two weeks in hospital the whole time.
"It was really tough seeing everything he went through and that's what is pushing me to compete at training and keep trying hard, to make him proud.
"Dad is going through what he is and the best thing I can do is play and perform to the best of my ability. My family is the whole reason why I'm here doing what I'm doing. If I keep playing well it will put a smile on dad's face."
Lifting his father's spirits is the fact he can now watch his son play for Broncos, which wasn't the case when his condition was at its worst.
"He is able to watch the games at home. He is out of hospital, so he only goes in to do his treatment and radiation," Isaako said.
"Beforehand, he was in hospital for a while because it was pretty severe and he wasn't able to watch games."
Isaako missed two games while he was in Christchurch but is now finding some of his best form, running for more than 150 metres in the wins over the Bulldogs and Titans and scoring a try in each.
He credits Brisbane's support in his darkest hour as being the catalyst for regaining his mojo on the field.
"I am starting to get some confidence back. How I've been playing hasn't been ideal, but the toll of finding out my dad has cancer, it really affected me and my season and my mind wasn't where it was supposed to be," he said.
"Speaking to the coaching staff here at the Broncos, when they let me go home for a couple of weeks to spend some time with him, that really helped and ever since I've come back I've found some confidence in how I've been playing.
"Hopefully I can keep it up and put my best foot forward for the team as we build towards the finals."
Through his own grief Isaako is still doing his best to be positive about the future.
"I've never lost anyone this close, so this is huge for me," he said.
"The doctors have said there is no cure for the cancer he's got. If we can keep staying positive and hopeful, then I'm sure he can live a bit longer if he does everything right."
Isaako is determined to put a smile on his dad's face with a strong performance as he marks Storm speedster Josh Addo-Carr on Friday night.
"It will be a good test for me on how well I've been going the last couple of weeks," Isaako said. "Hopefully I get a few more tries against him this week."