70/30 ETFs in a Special Needs Trust?

I am trustee of a special needs trust for my 53-year-old brother. He works for cash under the table and can support himself. There’s 175k in cash in a Schwab taxable brokerage account held by the trust. He should be able to work for the foreseeable future but in the next 15 years or so he’ll want to start drawing on some of the funds in the trust to live on. I am comfortable with some risk and want to be tax efficient. This is what I am thinking to do with the 175k and would like some feedback on if ETFs are the best choice at this allocation please: 50% in SCHB 20% in SCHF 30% in SCHZ Thanks for your feedback!