From The Peerage: Jacob was the son of Alison Margaret Worsley (b.1963) and Christian Holstein. They married in 1992 and divorced 1996. Alison married again in 1997 and her married name became McIntosh.
Our colleague, Andrew Behan, states that Jacob Sebastian Holstein was born on 11 November 1993, his birth being registered in the 1st quarter of 1993 in the Westminster registration district. His father was Christian David Von Holstein (1968-2008).
He died, aged 4 years, his death being registered in February 1998 in the Richmond upon Thames registration district.