My father's only income is from social security benefits and veteran's disability benefits. Does he have to file a tax return?

This can be very complicated. It depends on the amount (of income) and how the disability is considered.
You should speak to an attorney, preferably one associated with the VA.
A disability AWARD is different from 'usual' benefits. You need to know the difference (between award and disability benefit). And, your situation may be more/different from whatI had deal with so do check.)
Be aware that some employees in some of the VA departments do not know about these issues, which, unfortunately, further complicates it all.
Do google VA benefits and tax exemption. I have been through (some of) this although it had to do with a service connected Award which is not taxable.
I wish I could provide more clarify. "When in doubt, hire an attorney" (or in this case, see if one / non-profit attorney organization is associated with / to help veterans at no cost.

Gena / Touch Matters

srmoore: Pose your question to your certified public accountant.

Assuming he is not the dependent of someone else, generally, if he makes over $14,700, he needs to file a federal return, even if he owes no tax. Here in my state, it is always worth filing as there are other state tax credits that one could get as a refund, just for being a resident in the state.

Even if he doesn't have to file a federal tax return, it is worth filing a tax return. With computers, it is easy for the IRS to cross check income against tax returns. A more sinister problem is people who file tax returns using someone else's social security number. Filing taxes is usually the first place this type of fraud is caught by the legitimate owner of the SSN.

You don't need to pay anyone to file his tax return assuming that is all he is going to declare on his tax return. Most tax software allow multiple returns on the same copy of tax software. There are several legitimate internet sites like the IRS and Turbo tax, that offer free filing. In addition, AARP has Tax-Aide sites in all states which do preparation and filing of taxes for free. Before the pandemic, the Tax Aide group I was involved in, visited senior living centers.

BTW, Tax-Aide isn't only for seniors. They will do a wide range of tax situations including the forms due to being a self employed delivery person. However, if it has anything to do with depreciation or cost of goods, it is out-of-scope and Tax Aide can not do it. https://www.aarp.org/money/taxes/aarp_taxaide/

Just my opinion - I’m right at the $25,000 mark. I saw an article the other day that said: income + interest + HALF of social security = file.

It isn't a matter of where your Father's income comes from but what your Father's income is. I once knew, but things change, so don't count on this, but it was once that if your income is more than 14,000 you have to file. Doesn't mean you will have to pay taxes but you do file.
I would go to the IRS website which is a good one to ask this question once you know what your Father's yearly income is. There is a lot of free tax help out there also, so keep your eyes and ears open for his area. You need to be clear about the rules for both Federal and State.
Sure do wish you luck in getting the info you need specific to your Dad's case.
Also remember to go to search spy-glass next to your avatar; press that and type in taxes; there may be articles on AgingCare to help.

Yes

Everyone should file a tax return every year (as early as possible), regardless of income or IRS rules. That action will minimize possibility identity theft by a crook who could utilize your SS# as his/her own. IRS supports Vita/TCE no charge tax preparation programs through nonprofits such as AARP, United Way, etc.

My mother's income is a VA survivors benefit (which isn't taxed) and social security, which isn't much, so she doesn't make enough to have to file a tax return. BUT, I file one for her anyway simply because without a tax return on file, she would not have received any of the COVID stimulus checks or the latest middle class tax refund (California). Since she is considered low-income, she qualifies for free tax preparation software, etc.

My Mom received 1500 a month in SS and 200 in pension. Because her income was mostly SS she did not pay taxes. The IRS sent her a letter telling she no longered needed to pay. For ur Dad, it would depend on what his VA benefits total. There is an income cap. You cannot make over a certain amount. I would ask your tax person if Dad needs to pay.

Do the math using an online tax system (like H&R block) or paper 1090 that you can find online. It's very possible he's due a refund or he might even owe some taxes. After you calculate, at least you'll know to go ahead and submit or not

Thats pretty funny Alva.

https://www.irs.gov/help/ita/do-i-need-to-file-a-tax-return

The above is a link to the IRS page that discusses who must file a return.

You should find out how much of his Assisted Living payments are tax deductible.