EVTR
Eaton Vance Total Return Bond ETF
stock NYSE ETF

I agree with not getting involved in picking your parents' investments.
That said, VOO, VXUS, and even BND and SCHD are volatile in their own ways, especially for people who have a low risk tolerance.
Is this in a tax-sheltered account like an IRA? If so, I might consider something like low volatility funds -- QLV, VFMV, or LGLV for domestic, QLVD or LVHI for international, plus a TIPS ladder. Or a balanced fund -- most are mutual funds, so what is available will depend on what brokerage they use. AOA or AOR can be bought anywhere though.
Fidelity --> FFNOX or FBALX
Vanguard --> VASGX, VWELX, or VBIAX
Schwab --> SWHGX or SWOBX
For a taxable brokerage, the same low volatility funds work for equities. Maybe municipal bonds if they are going to be in a high tax bracket. If not in a high tax bracket, then investment grade corporate bonds or treasuries or both. I vastly prefer individual bonds to bond funds, but if you really want a fund, then I might consider DFCF, VCRB, EVTR, or IMTB.
For a balanced fund in taxable, AOA or AOR, or VTMFX if at Vanguard.

I agree with not getting involved in picking your parents' investments.
That said, VOO, VXUS, and even BND and SCHD are volatile in their own ways, especially for people who have a low risk tolerance.
Is this in a tax-sheltered account like an IRA? If so, I might consider something like low volatility funds -- QLV, VFMV, or LGLV for domestic, QLVD or LVHI for international, plus a TIPS ladder. Or a balanced fund -- most are mutual funds, so what is available will depend on what brokerage they use. AOA or AOR can be bought anywhere though.
Fidelity --> FFNOX or FBALX
Vanguard --> VASGX, VWELX, or VBIAX
Schwab --> SWHGX or SWOBX
For a taxable brokerage, the same low volatility funds work for equities. Maybe municipal bonds if they are going to be in a high tax bracket. If not in a high tax bracket, then investment grade corporate bonds or treasuries or both. I vastly prefer individual bonds to bond funds, but if you really want a fund, then I might consider DFCF, VCRB, EVTR, or IMTB.
For a balanced fund in taxable, AOA or AOR, or VTMFX if at Vanguard.