There may be some clues to this in 'Romanov Autumn' by Charlotte Zeepvat, contained in the footnotes to the chapter 'The Lost Tsar'. Derevenko was supposed to have been concerned about a suitcase sent to Tobolsk that contained one of Alexei's icons and a new suit meant for the Tsarevich to wear, and inquired about it - but I would have to read 'Le Tsarevitch - Enfant Martyr' by Eugenie de Grece, to find out more.
Derevenko is reported to have died in a place called Tifa in Russia in 1921. (From the book 'Tsesarevich' Vagrius Press, Moscow, 1998 ).