For you, it's as simple as 100% VTI.
For dad, he might do better with a 60% stocks (VTI), 40% bonds (AGG), plus or minus 10% depending on preferences.
Some pointers:
>Dad will want to consolidate his accounts into an online brokerage if he hasn't done so already.
>Set dividends to reinvest into more shares. Don't leave any cash sitting around uselessly.
>Efficient tax sheltering is key. You need to set up a SEP IRA or similar to shield up to I think $53k. Dad needs to do the same if self-employed, or contribute as much as possible to his employer's 401k.
>The #1 determinant of retirement success and risk reduction is frugality. For every $1 you permanently cut out of your annual expenses now, you not only save $1 but also reduce the need to save by $25. So if dad cancels his $50 cable package for good, that's equivalent to putting $1250 in savings.
>Dad is in a nightmare scenario. He's a few years from retirement without nearly enough saved and invested. His quality of life will fall dramatically in a few years unless he gets hardcore with the saving. He may be moving in with you unless something is done. If he could target a 40-50% savings rate for the next 7-8 years, retirement might not be so bad.
>Even worse, dad is working in a profession with a high risk of injury. Some long-term disability insurance might be in order here, so that his savinga aren't depleted after a fall, back injury, stray nail, etc. Make sure he's wearing a back brace, steel shank shoes, glasses, gloves, etc.