I know there have been recent changes to the Kiddie Tax tax rate(now back at parent’s highest marginal rate) vs. Trust tax rates.

My question is 2 part and may be more of a tax questions than IRA.

I have a Bene IRA for a minor (dad) passed in 2018 and is taking annual stretch payments and slightly more to fund 529 plan. The RMD amounts are approx. 15k(gross). 1st question is; his mother’s (widowed) net income right at 24% marginal rate. Does the GROSS RMD of 15k or amount after slight deduction get tacked on to mother’s net income to derive at the 32% rate? I know this doesn’t effect the mother’s rate but puzzled what the kiddies tax rate would be in this example ( 24% or 32%). Their accountant couldn’t provide an answer until they run return, so much for planning!!!!

2nd question,

Minor’s mother passes and Guardian will be named for minor and may need $50,000(gross) annually for general living needs. Since both parents would be dead does the RMD income status now change since all the $50,000 would be for the minor’s support? Their would be no earned income and lets say minor is age 14 when mom dies? Since there is no parent’s tax return to determine marginal rate didn’t know what the rate may be in this example?