Can anyone advise on the death of an estranged part in a Civil Partnership?

[WhatNowThen]

I wonder if anyone can help me with this.

May be a slightly long convoluted story but I'll try to keep it succinct and to the point.

Two male friends of mine entered into a Civil Partnership some 9 or so years ago. They were together until 2008 at which point one of them left the union due to infidelity, financial dishonesty and unreasonable behaviour.
At around this time I too ceased to be friends with this person (mainly the same reasons) and little more was heard from him. I knew that he was HIV+ but nowadays that's no longer the death sentence it once was.
His partner also knew that.
The estranged partner returned to his homeland - Germany and although there were attempts by the other person to rekindle the relationship he was resolute that it was over. A dissolution of the union was refused him and he, probably unwisely, decided to bury the whole thing and not deal with it. He did make tentative enquiries about a year ago but his German lawyer told him it would be difficult and expensive to do from there and so he shelved it again.
News has just reached us that the UK based partner has now died. I guess that without me having been told then the Germany based partner might never have known this - but I don't know that for sure. Anyway - he knows and is dealing with whatever emotions this throws up but has absolutely no idea if he has to do anything about anything and I have no idea either - or any idea of where to direct him. I wonder if anyone here might know?
Thanks in advance for any advice.

Glaring typo in the title thread - part should of course read partner

I am unsure what exactly the question is. They were separated and I expect the deceased relatives will deal with funeral and will be his heirs.

If the question is will the heirs to the estate be the family or the partner - I would think that the partner needs to find out as legally he may well be the next of kin and entitled to the estate - this could also depend on whether a will was left.

He should apply for a copy of the death certificate too so that if he ever wants to marry again he'll be able to prove that his former partner is deceased. Otherwise though, I'd think he should contact his former partner's family to express condolences and to ask if there is anything he can do/needs to do.

Thank you Juneau - and sorry if it wasn't apparent what I was asking (you're right btw, it wasn't and for that sorry!) - I don't think he has any intention of finding out if there was anything left. There won't have been. The deceased was a habitual bankrupt in the last five years and estranged too from all of his living family.
I suppose he just wanted to know if he actually has to DO anything - and I think Juneau has answered the question I so spectacularly failed to ask!