I'm probably missing the point entirely here @rosecin, but for the planting part of the task you are actually quite lucky to have stoney ground, as most plants like free draining soil - unless they are bog type plants. So all you need to do (unless you want a very big flower bed) is dig up - with a spade - the top layers of soil, and store it in a strong black bag in a shed or your garage, and use a handful of that stoney soil in the bottom of plant pots in the future.
You will then need to fill in the space left by the dug up soil, with top soil, which depending what type of flowers/plants you are planting, will probably need some type of 'treated' additives, or it might need to be an acidic soil rather than an alkaline one. The labels on your plants, and the soil that you buy, should have what sort of conditions they need, etc.
If your children are toddlers or infants, and you bought them tiny children's gardening kits, they would probably love to help you, and/or daddy - in fact if you have a big enough plot, children often seem to enjoy planting their own seeds, and watering them, and watching them grow. Light gardening really can be a fun activity for all.
Unless your "builder" is a hobby gardener he might not know anything about garden management, and his brawn might not be too helpful on it's own! Also, and this is only personal, I would be too embarrassed to ask someone who calls himself a builder, to do something as easy as putting hanging baskets brackets up. During my period as a single Mum I was quite proud of teaching myself things like that, and how to re-tile my bathroom, and change fuses, and wire plugs etc. and that was before the Internet, well maybe Pacman had started on PCs, but it was definitely before YouTube et al.
Sorry OP, I started this ages ago, but then my husband brought our dinner in - he is my carer as well, and has to all the jobs now, as I am virtually bedbound these days, how I wish I could still garden and do DIY! Anyway we just finished our very nice meal recently, and I have come straight back here before I get on with learning the foreign language that I am currently studying - aren't Smart phones wonderful, well within reason...
However you decide to tackle your present problem, please don't forget to make some time for whatever your family do for fun, as at the moment you sound very busy. Here are some 🥀🌻🌷🌾 to start you off! 😉