| Quote #4
…shortly afterward he had set to work, alone, digging the grave in the place that Bill had shown him at the end of the garden, between bushes. He dug with a kind of fury, relishing the manual work, glorying in the non-magic of it, for every drop of his sweat and every blister felt like a gift to the elf who had saved their lives. (24.7)
Harry's grief at Dobby's death reflects his guilt and pain at the idea that others make willing sacrifices for him. It hurts more than anything else to think about the fact that those he loves, like Mad-Eye and Dobby, are ready to give up their lives for him.
| Quote #5
"My brother Albus wanted a lot of things," said Aberforth, "and people had a habit of getting hurt while he was carrying out his grand plans. You get away from this school, Potter, and out of the country if you can. Forget my brother and his clever schemes. He's gone where none of this can hurt him, and you don't owe him anything." (28.43)
Aberforth bitterly notes the tendency for people to get hurt by Albus's schemes, even if they're for the greater good, and doesn't want Harry to willingly give himself up just to finish the path that good ol' Albus started him on.
| Quote #6
"[Albus] told me I had to finish my education and he'd take over from my mother. Bit of a comedown for Mr. Brilliant, there's no prizes for looking after your half-mad sister, stopping her blowing up the house every other day. But he was all right for a few weeks… till [Grindelwald] came." (28.69)
We finally learn what happened to the Dumbledore family – it seems that young Albus was ready to sacrifice his early career to take care of Ariana. But his was not entirely a willing sacrifice, as demonstrated by his easy distraction by Grindelwald's charms.