2015 OB- Neglected Maintenance - Recovery?

[arcsound]

Just learned that my MiL's 2015 OB, purchased new, and now with 84,400 miles, has only had periodic oil changes (and new tires, at least once). No major maintenance performed.
Wondering what are the most critical maintenance items she should do ASAP?
Here is my short list:
- coolant change
- brake fluid change
- transmission fluid drain and flush

What are your thoughts on:
1. urgency for each?
2. other items, including the timing belt & water pump?

Thanks in advance!