You don't say where your father is from. Has Fidelity specifically told him he needs a US ITIN? If he's a Filipino citizen living in the Philippines, first ask whether they'll accept Form W-8BEN with his Philippine TIN. It depends on the type of account and claim. If Fidelity confirms an ITIN is required, look for an IRS-authorized Certifying Acceptance Agent (CAA). The IRS has an official directory, including a Philippines section, where you can verify an agent: https://www.irs.gov/tin/itin/itin-acceptance-agents

You can contact the Jim Boyd Foundation, RAO in Angeles City. I got the correct name from the IRS website. I won't give out the phone number, but if you Google the foundation's name plus Philippines it should come up. You have to make an appointment, so you'll need the number. They got an ITIN for my wife and it was very inexpensive. They also helped by mailing off my amended federal tax returns for the last three years, which I prepared and signed. They only charged for the postage. They also handle veterans' affairs information and Tricare filings. It's all volunteer-run and very much appreciated.