Millie is not a bad mother. Did she abandon her kits and not bother treating them nicely when they were kits and apprentices? No, she didn't, because she cares about them. She looked after them all her life and almost died when they were just kits. Millie was a very overprotective mother who was close to spoiling her kits so much and only cared for them.
Her kits were almost warriors by the time Briarlight got paralysed. Her own kit was crippled for life. That isn't something that can be easily ignored. Millie does not spend all her time with Briarlight although she would need it anyway. People complain about Millie "neglecting" her kits who can look after theirselves yet they let Graystripe off with it when he doesn't ever interact with any of them!
Millie has the right to worry about her kits; she's never been used to the wild as she's been a kittypet for most of her life. Keep in mind Briarlight has had so many near-death experiences and almost died twice as a kit: from greencough and a snake. Jayfeather barely even reassured her so how was Millie going to be all right after her kit almost died before? She was crippled.
"Millie gasped. "What do you mean? Broken bones mend."
"Not backbones."
"How do you know that?"
"Littlecloud had a warrior with the same injury," he [Jayfeather] told her.
Briarpaw was craning her head to him. "What happened to him?" she mewed.
Jayfeather didn't answer.
"He died, didn't he?" Briarpaw whimpered.
Jayfeather felt Millie barge into his shoulder, shoving him until she had bundled him right out the den. "How could you tell my kit she was going to die?" she hissed. "She can't feel her legs, that's all! You're not fit to be a medicine cat! Do something!" - Fading Echoes, page 174
Jayfeather never really said much to calm Millie down. Wildfur only died in a matter of days after getting his injuries and it's just pure luck Briarlight has lived this long. Hearing a cat dying from the same condition Briarlight has is only just going to make Millie more panicked and stressed. Millie cares. People complain about Rainflower doing the wrong thing but when Millie does the exact opposite, they still whine. Would you want Briarlight to be rejected by her mother just like Crookedstar?
Millie's being hysterical like Bluestar and Dawnpelt were--and she has the right to be! People hate both Dawnpelt and Millie for going hysterical yet Bluestar seems to get more love from it. That doesn't make sense. And for all we know, this could have been Millie's first litter of kits! Mothers always worry about each and every kit. Briarlight could even die at any moment and is lucky she's still alive.
Millie's faith was wavering; her kit almost died three times and she was likely to be losing faith since she probably thought she'd lose her kit, especially when Jayfeather didn't help by telling her not very stubly that Briarlight was never going to walk again, causing her to snap. Millie's actions are full of good intentions. She probably does know Briarlight could die any day since she had more than five near-death experiences. I can see why she'd be very panicky and hysterical.
"Faith?" she [Millie] hissed. "If your warrior ancestors are so powerful, then why don't they cure her [Briarlight]? If this happened in my old home, my housefolk would have fixed her."
"Millie?" Graystripe's shocked whisper sounded from the entrance as he padded into the clearing. "Is that what you really think?"
Millie backed away. "I don't know what to think," she rasped. "I only see my kit, broken and helpless, struggling through each day, with death stalking her like a fox. . . ." Her mew trailed into silence.

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Warrior Cat Rants
RandomWarriors is a good series, I'll admit, but some things just make me mad. Here is where I'll be posting on the things that bother me from the Warriors books which will most likely contain spoilers for certain books. Some of these, however, may not ex...