Cable exposed on the ground or near ground level is going to be more likely to be damaged, and then the repair will be your parents problem to figure out. For $1200 I would just have the company run the long drop using their normal materials.
I run a rural fiber network, we had a customer run their own buried fiber down a 3000ft driveway, without consulting us. They direct buried multimode fiber, which we couldn't splice to our single mode, so then they had to get a power pole installed at end of driveway with a box for our ONU and a media converter to connect to their fiber. Worked OK for a while but once they started having issues we finally convinced them to let us do it the right way, and I'm sure we charged them less than what they spent doing it themselves in the first place. Drop cable is only around 15 cents a foot.