It means the brothers could become the latest family members to play in the same team at the same time, with the younger Fa'asuamaleaui likely to push for a debut in the coming year or two.
The Titans confirmed on Friday morning that he will be signed on a development deal for the duration of the 2023 season, before progressing to the Top 30 squad at the club for the 2024 and 2025 seasons.
Fa'asuamaleaui has been part of the Titans' development program, and made his QLD Cup debut for the Burleigh Bears during 2022, where he played 14 games during the year.
Playing as a prop, the young gun made 74 metres per game despite playing limited minutes, while also adding 11 tackle breaks and tackling at almost 95 per cent during his time with Burleigh.
That's where he will start the 2023 season as he takes up his full-time development contract at the club, and coach Justin Holbrook said he was excited to watch the youngster's continuing progression.
“Iszac is a familiar face around Parkwood, having come through our junior system and having done some work with us on the training field last year,” Holbrook said in a club statement.
“He's also been involved in the admin side of the business as a trainee, so he's got a real understanding of the club and what we are looking to build here on the Coast.
“He's a middle forward like his brother and while he has a lot of the same traits that we see in Tino we're also keen to see the evolution of Iszac as a player in his own right.
“In our first week back for pre-season, he is already setting the standard and is consistently at the top of our fitness testing which shows the type of athlete that he is.
“He's a hard worker and someone who is keen to learn and I've no doubt that we'll see him join his brother in a Titans jersey in the not too distant future.”