Wait a bit longer - the damage to various JMs around here went from a few injured leaves to complete defoliation, depending on the tree and the location. Some have begun to grow new leaves and some are still sitting there. As long as the cambium - the layer right under the bark - is still green when you scratch lightly on a twig, the tree is alive. You may have some tip die-back to trim off, but the tree itself should be fine. Most trees have auxilliary buds; they will grow and leaf out soon. Wait until the leaves are clearly growing before you do any trimming, and be careful of the emerging leaves. Resist the temptation to clean off the old leaves, unless you did it straight away - you might damage the emerging buds. Water the tree well, but don't drown it, as JMs don't like standing in water. And don't fertilize until the tree has almost all the leaves out, and then lightly with a slow release fertilizer.

If you are gardening in California, and a zone 9 designation would seem to indicate that you aren't located in coastal southern California, then most all of the red leafed maples will grow well in northern California if well watered and located out of the wind. The dissected leaf cultivars need even more shelter from full sun and hot drying winds to look their best. If the weeping dissected leaf forms are what you want, be sure you can locate it out of wind, give it sufficient water in summer, and probably best with dappled bright shade or morning sun only if you are away from the immediate coast. The red coloration of foliage is always less red in mid summer, brightest when first leafing out, and again when cold hits and they start to color up. I wouldn't bother planting one if you can't give it ideal conditions, as they will look rather beaten up with dried out leaf tips if they aren't happy with the spot. If you have hot sun and want drought tolerant, you could always substitute with the Purple Smoke Bush, Cotinus coggygria 'Royal Purple', which is probably a better choice for a California garden in any case, because it can survive with much less water in the long term. You might also consider the purple foliaged Willow Leaf Peppermint Tree, Agonis flexuosa 'After Dark', which is evergreen, weeping in form, and has deep purple foliage year round.

Reasonable request to tree service would be to go to a local nursery and find a replacement, and whatever it costs, it costs. Not really your problem, its his, no matter the cost. He has insurance if he is a reputable tree service, so most likely wouldn't come out of his personal pocket anyway. Good luck, let us know what happens.

Can you post photos? It's a little difficult to tell from your description just how severe the damage was and that will determine what your course of action should be going forward. Remedial pruning of a grossly mispruned J. maple is a tricky business.....they may never regain their former appearance. FWIW, depending on cultivar, $300 for a mature JM is very conservative :-) I've seen them go for as much as multiple thousands. And going forward, I'd make sure your dad was politely instructed NOT to undertake any more yard work without your express permission and direction.