good question. I have thought of it before. I'm going to assume that their ladies' find out about it by themselves along the way during dating period (through last names). Plus it also depends how they met them. Maybe they might've met them through knowing who the guys are in the first place. Considering the women end up marrying them and having kids, It really wasn't a problem at all who their deceased younger brothers were cause them as their own men individually would've been just fine.
I'm sleepy.
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Will you remain my fire in this temporary paradise?