According to the papers the burglar was a serial offender, almost all his crimes involved conning elderly people out of money. He and several uncles and his father were cowboy builders and cheated one man out of £72,000 to replace one tile.
Altogether an unpleasant piece of work. I will not say he deserved it, what he deserved was a long spell in prison, but if you go out to break into someone's house, especially armed with a screwdriver, which can be just as dangerous as a knife, while not attracting the long sentences that knife crime entails, and I bet he did that deliberately, then you must take what comes, and in this case someone protected themselves from being stabbed by his screwdriver, by stabbing him with a knife.
As for the relative, as coming from a family of cheating conmen and thieves. If they, as a family, had brought the deceased up to be decent and honest and earn an honest living then he wouldn't have been in someone's house in the middle of the night threatening violence.