Helping family in another state fix their car, but they aren't allowed to have money in the bank

Edits- Thank you to everyone who chimed in and shared their experiences and advice. Overwhelmingly the best idea is to call the car repair place and make a payment over the phone or see if they have other website or electronic options. walmart 2 walmart seems to be the safest bet for sending cash that won't be tracked. I hate the system that says people need to stand in line at a place (maybe for an hour?) with the kind of noise and light that triggers migraines. Being charged 15% to send money to your family. Having to drive around a hoopty because you aren't allowed to have enough money to have it repaired. I am grateful that I can help a little bit. // End edit.

Hello, my folks really need to get some repairs done on their vehicle. They live a few states away from me. Due to their housing, food, and other health/human services programs, they cannot have more than $1,500 or $2,000 in their account. I'm seeking ways to help with the needed funds, without getting in trouble with their benefits.

A USPS money order seems to make the most sense, but the post office in their small town doesn't keep more than about $100. The last time I tried it, they had to go to Walmart and wait in line for over an hour.

Uncertain if money orders or western union are tracked so I'm not sure I want to take that chance. Thank you for reading. I really will appreciate some advice.