How do I prove a death?

A couple of weeks ago a close family friend passed away and since I’ve had trouble concentrating on uni work. Because of this an assessment that I have isn’t complete to the best of my ability. I’ve submitted an extenuating circumstance form asking for an extension but they’re requesting evidence. This would be fine except the family of said friend really do not like me as they believe I’m the reason for said friends sexuality, therefore I can’t get a copy of the death certificate from them and I’m not sure what else I could provide. I’m really stuck and could use some help please.

A couple of weeks ago a close family friend passed away and since I’ve had trouble concentrating on uni work. Because of this an assessment that I have isn’t complete to the best of my ability. I’ve submitted an extenuating circumstance form asking for an extension but they’re requesting evidence. This would be fine except the family of said friend really do not like me as they believe I’m the reason for said friends sexuality, therefore I can’t get a copy of the death certificate from them and I’m not sure what else I could provide. I’m really stuck and could use some help please.

As gjd800 said, check that the university will even consider this claim - a lot of institutions will only consider ECs due a death if it's immediate family.

They do. I’ve already submitted the claim and it’s been accepted they just need evidence to give me the actual extension

https://www.gro.gov.uk/gro/content/certificates/faq.asp

"Records we are not able to provide

"GRO is not able to issue certificates for events that have taken place within the last six months (for marriages this period is extended to eighteen months) and you may wish to obtain a certificate from the register office or church where the event was registered. This information excludes adoption certificates, as the local register office does not hold a copy of the Adopted Children Register. If you require further information please call 0300 123 1837 to talk to our customer service team."

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As the death was recent, might it be possible to get a copy of the funeral service (it demonstrates you attended) or even a death announcement instead?
Alternatively, could you get a sick note from your GP? That might be easier to obtain in terms of evidence