Viljo died in the 40's, not at an early age, as suspected.
What is the source of your information? Wiljo Hamalainen's biography on ET indicates that he died in 1914 due to endocarditis, aged 3 years and a bit. There is even mention of the cemetary where he rests and so that information must be right.
That is a pity because I was hoping that Wiljo had lived to adulthood and had a family of his own. Although only a baby at the time he was saved from the sinking
Titanic, had he lived and grown-up, his mother might have told him details of their survival and perhaps how and why their co-passenger Martta Hiltunen did not make it. She, Martta, has been the subject of my research for a few years but I have managed to get only limited information thus far.
However, there seems to be more information now on ET about Ana Hamalainen after her own rescue from the
Titanic. Her divorce from husband 'John' and eventual remarriage. I am not sure how much she would have discussed with her second husband and stepson about her survival but IMO worth looking into.