Parents have 10K to invest in the market stocks

My parents have had about $10K in a savings account not growing and want to invest it in the market. They are late 50s, do not need the money now or the foreseeable future, though they they said they might, so this $10K might actually be $5K while keeping the other $5K liquid. Whatever gets put in the account wont be touched. I was thinking just invest it all in an index fund (VTI) perhaps, as its relatively safe compared to me picking stocks (Im ok losing my own money on stock picks, not someone elses money lol). Should I do a certain % in equities then pick individual stocks with another fixed %?

My parents have had about $10K in a savings account not growing and want to invest it in the market. They are late 50s, do not need the money now or the foreseeable future, though they they said they might, so this $10K might actually be $5K while keeping the other $5K liquid. Whatever gets put in the account wont be touched. I was thinking just invest it all in an index fund (VTI) perhaps, as its relatively safe compared to me picking stocks (Im ok losing my own money on stock picks, not someone elses money lol). Also what is the best provider? Vanguard? Should I do a certain % in equities then pick individual stocks with another fixed %? Also, Im sure this gets asked a lot, but should I try to wait for a dip or a mini crash to happen since the markets are so high? I know you cant time the market so I may have answered my own question, and I thought the same thing in February when I parked a lot of my own money in investments. What do you guys think about the current levels of the market? Thanks for any input!