Don't be scared. Your mom has multiple ties to Pakistan (your dad + younger brothers). As she has already visited once, two years ago, it would help especially because she has not been visiting often nor did she seek an extension.
Do post:
1. Purpose of her intended new visit + for how long
Just to visit us for a month as she is missing our 22 months old son, due to my job and my wife MSc studies we cannot go back home for more then 15 days and I don't want to go 16,000 miles and spend 5K in tickets for just 2 weeks
2. List of documents + if there's any change to her personal situation as compared to her previous TRV app
Previous application my dad was principal applicant therefore we didn't provide any documents for my mom. We can provide bank statement from Pakistan, from our side my wife's official transcript, my job letter our joint bank accounts for financials. Last year NOA for both of us
3. Can she include any must-return-to-Pakistan-by-a-specific-date reason with evidence?
The only reason is my brothers are living with parents at same address
4. Will your dad accompany her this time? How old are your brothers now and are they both studying?
No, my dad will be planning to visit next summer as he has some knee problem and do not want to travel. Younger brother 27 (working full time) and youngest brother is 22 (studying full time Bachelors of business administration in 3rd year)