F 5329 - use it to request a waiver of the penalty (which, to my knowledge, has never been denied).  This Form can be filed separately.

Explain what's been done to make sure future RMD's are taken timely.  Request the missed one from the fiduciary and make sure the current year one is scheduled before year-end.  Your client will get a F 1099-R that will include BOTH RMD's for 2019.