there is one additional tax issue. since one received more than $2300 of distributions that income is unearned income and so the kiddie tax applies. the other isn't subject to the rule.
https://www.kiplinger.com/article/retirement/t032-c032-s014-beware-of-kiddie-taxes-when-leaving-heir...
when the kiddies tax applies the options are for the child to file their own return but must include form 8615 which requires the parent(s) to complete their return first or the parents to include the amount on their return using form 8814. that child does not file a return
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