Had the biscuit
Wondering if anyone has heard the explanation re Phrase 'had the biscuit', that it derives from WW1 trench warfare in France. When a soldier was mortally wounded the Chaplain administered 'last rites' which included the Eucharist---wafer of bread---which in soldiery slang became 'the biscuit'. Ergo, if so-and-so 'had the biscuit' he had died. It bcame applicable to almost anything that was 'worn out', 'finished.
I can't speak for any other Christian denomination (but I strongly suspect they are similar) but in the Catholic Church the Sacrament of Extreme Unction (the 'last rites') does not involve taking the consecrated Host, but in anointing with oil.
It might be rather difficult trying to get someone on the point of death to swallow a 'biscuit' - or indeed, anything else.
DFG
In the Catholic Church, "Last Rites" consists of 3 parts depending on what the person is capable of - Penance (confession), Anointing of the Sick (the official name for Extreme Unction since Vatican II), and a special Eucharist called a Viaticum (provisions for a journey) which would include wine and wafer if the person is capable of ingesting food. (It's only a wafer-thin wafer after all).
Most Protestant denominations outside of Anglican/Episcopalian do not have such official "about to die" rites at all.
Nothing official for us Baptists, I don't think. But a confession of faith -- accepting Christ as your savior -- is a good idea at the point of death (and otherwise) if you haven't already done so. Reminds me of a story about W.C. Fields. During his final illness, he was seen reading the Bible. Mr. Fields said, "I'm looking for loopholes."