Father died 2014. His stock sold in 2018. Merrill Lynch sent 1099-R. Turbo Tax asking if I received all RMD for 2018. How should this be answered?

who has been handling his Estate for the last five years. ?

If the box 'Total Distribution' is marked on the 1099-R, then RMD does not apply and you could answer No.

If not, and you are continuing to receive monthly payments for sale of stock from Merrill Lynch, and your father was over 70-1/2 when he died, you can answer Yes. 

Here's more info about RMD:

https://ttlc.intuit.com/replies/3302117