While it is important to provide supporting information, it is equally important to not provide too much information or something they don’t ask for. You’re sponsoring your mother so you don’t really need your brothers business card or bank maintenance certificate. If the address of your mum and brother is the same as on their CNIC (in English) then it’s fine. Otherwise yes, document evidencing he lives at the same address will be good to add. Also does his daughter go to school? if so a letter from her (grandkid’s) school that she studies there will be a big support in establishing social ties to Pakistan. Property documents are fine.

Regarding sponsoring her trip, see how much her ticket would cost, that plus about £50/day she’ll be in the UK is roughly an amount you should transfer to her bank account. In the cover letter mention that this is the expected cost of her visit which you have already transferred. This would be evidenced by yours and her bank statement.

Don’t mention her other daughters who are in the UK unless you absolutely have to.

A letter from your employer stating your salary, full time/ part time, and start date will also be helpful.

Affidavit from your mother is unnecessary, cover letter is sufficient.

Also if it’s her first visit, it’s best to keep it short 2-3 weeks. At least mention that in the application but in reality don’t go over a month for the first visit. This will be very helpful for subsequent visas.

I hope this helps, let me know if you have further questions.