I don’t work with DB plans – All help is appreciated

DB participant died in 2020

Adult son – sole beneficiary

I am being told the son is eligible for lump sum distribution – a IRA rollover is one available option

Question:
Son wants to convert the lump sum to a Roth IRA – For example, the inherited lump sum value is $20k.  He wants to rollover (convert) the $20k directly to an inherited Roth IRA.  I know this is permitted in the DC world (non spouse benefit can converted an inherited account to a Roth IRA) – Does the same rule apply to DB plans?

Assuming a conversion is permitted – Is the son now subject to the SECURE Act’ 10-year payout rule?

Thank you