Personally if I felt the need, I would use an hourly FA to get things in order, then manage myself. Since I'm pretty knowledgeable about such things (after quite a bit of study and reading, and a little practice) I don't use one. However, I understand the question well as my DW has zero interest in how to make the money she wants to spend. As long as green crosses her palm when she wants something, she is right as rain. I do expect, however, that my demise will be before hers, given longevity in her family and in her overall gene pool (she's Japanese). Therefore, at some point, I would be wise to take on an hourly adviser just to have the contact, so she knows where to go in the case of an early demise for me. On the other hand, if I can train my DSIL and DD well enough and early enough to help her out without giving away too much about our assets, then I would prefer for her to have them to lean on. If that does not appear to be possible, I will at some point buy an SPIA to make sure DW can survive, and prepare to have an FP/FA help with manage the rest when I'm gone. I also have a son. Love him to death, but at 26 (same age as DSIL) he still does not even show the beginnings of the mental/intellectual capacity to cope with helping his mom manage large sums of money. He would either flub it really big and really fast, or take undue advantage.
As for how to train the kids, I intend to start a brokerage acct for each of them, donate a starting position, and help them decide how to manage it. Then, if the next 4-5 years or so are good one for the markets, I will begin making matching donations to each of their accts, up to the tax free gift limit. I will instruct the kids that this is their money, but that they cannot use it for anything except up to maybe half, but only for funding the down payment on their first home, and for their own eventual retirements. Using it for anything other than that would cause a halt to future matches. Upon my demise, there would be no restrictions, but by then I would hope that they had learned to be skillful with managing their money. DD and DSIL are already showing promise. DS and DDIL are not.
FWIW...
R