This ACAS guide aimed more at employers but might be useful
www.acas.org.uk/index.aspx?articleid=4977
You could give ACAS a ring to check.
As others have said, he needs to check his employment contract. There is sometimes an entitlement to bereavement leave otherwise it is covered by compassionate leave. However, there is also a right to unpaid emergency leave under s57 a Employments Rights Act 1996
"
Time off for dependants.
.
(1)
An employee is entitled to be permitted by his employer to take a reasonable amount of time off during the employee’s working hours in order to take action which is necessary—
.
(a)
to provide assistance on an occasion when a dependant falls ill, gives birth or is injured or assaulted,
.
(b)
to make arrangements for the provision of care for a dependant who is ill or injured,
.
(c)
in consequence of the death of a dependant,
.
(d)
because of the unexpected disruption or termination of arrangements for the care of a dependant, or
.
(e)
to deal with an incident which involves a child of the employee and which occurs unexpectedly in a period during which an educational establishment which the child attends is responsible for him.
.
(2)
Subsection (1) does not apply unless the employee—
.
(a)
tells his employer the reason for his absence as soon as reasonably practicable, and
.
(b)
except where paragraph (a) cannot be complied with until after the employee has returned to work, tells his employer for how long he expects to be absent.
.
(3)
Subject to subsections (4) and (5), for the purposes of this section “ dependant ” means, in relation to an employee—
.
(a)
a spouse [F4or civil partner] ,
.
(b)
a child,
.
(c)
a parent,
.
(d)
a person who lives in the same household as the employee, otherwise than by reason of being his employee, tenant, lodger or boarder."
So he may be able to claim emergency leave if he needs to do anything in relation to his DM death. e.g. DBs and I jointly arranged our DF funeral which was 200 miles away from where I live and work so I did take 2 weeks off (which my company chose to pay me for although payment was discretionary).