Muggles' Guide to Harry Potter/Characters/Walburga Black

Overview
The late Walburga Black is seen only as a portrait on the wall at Number 12, Grimmauld Place, her ancestral home. She is introduced to us by her son, Sirius Black. Her husband was apparently Orion Black, never seen in the books, but mentioned in passing.

Order of the Phoenix
We first see Walburga when Nymphadora Tonks knocks an umbrella stand over in the hall at Grimmauld Place. The curtains covering Walburga's portrait fly open, and she starts cursing the inhabitants of the house, as being Mudbloods and Blood traitors, among other things. Her screaming wakes up the other portraits in the hall, who join in. Nobody can get her to shut up until Sirius appears from the kitchen and wrenches the curtains over her portrait shut. Sirius then comments that he sees Harry has met his mother. He later says that he had been trying to remove her portrait from the wall, but she had apparently put it on with a Permanent Sticking Charm.

When we are later introduced to Kreacher, Sirius tells us that he has been taking instructions for ten years from the portrait of his mad mother. He also, showing a tapestry of the Ancient and Honorable House of Black, mentions that Walburga had evidently burned a hole in the tapestry anywhere there was mention of someone who was not true to her standards of Blood purity. Sirius points out the holes in the tapestry where his name and Andromeda Black's had been, saying that Andromeda had been burned out of the tapestry for daring to marry a Muggle-born, Ted Tonks. Apparently Walburga had also used a Permanent Sticking Charm on the tapestry, because they could not remove that either.

We hear her screaming again when Harry is leaving for school.

While she is certainly still present at Christmas, we don't see much of her then.

Deathly Hallows
When Harry first returns to Grimmauld Place with Ron and Hermione, the portrait of Walburga starts screaming at them as soon as they enter the hall. Harry, as the owner of the house, is able to shut her up quickly with, apparently, a single spell.

While she no doubt remains present in the hall as long as the Trio are there resident, she is part of the house at that point and the Trio don't particularly pay her any heed.

Strengths
Evidently, Walburga was a strong witch, and very strong-willed. Unfortunately, our only experience is with her "half-mad portrait", which leaves us very little to judge by.

Weaknesses
Being a painting, and apparently unwilling or unable to leave her own frame, Walburga can do little apart from scream. Her only way of accomplishing anything is by ordering Kreacher around; in the absence of any commands from the rightful owners of the house (initially Sirius, and later Harry), Kreacher will take Walburga's orders.

Relationships with Other Characters
Walburga was angry with her son Sirius because of his rejection of the Black family Pureblood values, and his leaving the family home to stay with James Potter's parents at age 16. It was because of this apparent sympathy for Muggles that she disowned Sirius, blasting his name off the tapestry of the Black family tree. It was a similar action on the part of her brother Alphard that got him similarly disowned and removed.

Sirius tells us that she had liked Regulus because he had remained true to the family Pureblood beliefs. It is uncertain whether she approved of his becoming a Death Eater, but it is certain that she did not disapprove.

Questions

 * 1) Did Walburga treat Kreacher well, or not? If not, why he talking to, and taking instructions from, her portrait?
 * 2) When did she die?