Thanks for your note... I am sorry to say that I can't find an entry for Frederick J. Husted with the Imperial Hospital Corps.
I have checked the enrolment/attestation forms and also the Nominal Roll but there is nothing recorded for the name of Husted.
There is however a record of a FG Husted, perhaps the G is a J?, this listing is with the Imperial Bearers Corps (WO 126/51), I don't have the enrolment papers photographed yet, but it is on my to-do list when I am next down at TNA.
Having said that I have checked the Nominal Roll for IBC and he is not listed on it, he is however recorded on the Medal Roll for the IBC, thats not uncommon and hopeful he will be on the Enrolment Papers.
Hope that this makes some sense..