There is no statutory entitlement to paid bereavement leave so this is governed entirely by your contract.  Your employee would have the right to time off but only the contract will set out if that is paid. Do you give paid bereavement leave normally?
 
Look at the terms of your contract and see what it sets out in these circumstances. If your contract allows for paid leave then you would normally pay them for those days when they would otherwise be working.
 
Do they have a regular pattern of work or are they already on a rota to work the days they need as leave? If they are expected to work that time and need to take it off as leave then that will probably activate your contractual term.  If they are not expected to work and don’t need to take leave then they probably won’t activate the contractual term.

See also: Leave IT to the experts