I think it is time to start over. As mentioned above. Kill the weeds with an herbicide like round up. There are other persistant weed killers so be careful because some of them will be active for a year and you won't be able to plant anything then. You will have to water and weed repeatedly to make sure you get the weed seeds as well.
After the weeds are taken care of and they are not coming back, amend the soil, it is probably compacted and has little or no organic matter. You will need to scrape off the old dead stuff and dump it, do not try to compost it. Amend the soil with compost. If you have a truck and have a composting facility near you it is cheaper to buy it by the truckload. They will deliver but the delivery charge costs more than the compost.
In the meantime check out the types of grass recommended for your area.
Your local master gardeners can assist you with choosing the kind of turf that is recommended for your area
https://cels.uri.edu/docslink/safewaterP ... hyLawn.pdf
Renovating a lawn is a lot of work. There are several landscape and turf companies that will do it for you but it will be costly if you don't learn to take care of it afterwards.
Install a sprinkler system. New lawns need to be watered up to 4 times a day until they are established. People who handwater usually don't stand in one spot long enough to deep water.
If you have the lawn installed get a maintenance contract for a year from the installer. Usually if you get a package deal the installation and maintenance contract together it comes out cheaper in the long run. Make sure you get instructions from the installer on how to take care of the grass and you follow his advice on watering. Learn more about how to care for your lawn and learn how to test if it needs water or if there are pests, how to take care of that.
The maintenance contract for the first year is important, especially if you think you are going to plant or install grass and it will take care of itself. Well, it doesn't. Home owners pay to have a lawn installed and blame the landscaper when it dies, but it is really the homeowner's fault for not doing the after care like watering 4 times a day because they opted out of the sprinkler because it cost too much. Weeds will still come through until the grass is established and can compete with the weeds better. Maintenance contracts should usually specify 75% weed free, a fertilizing schedule, and a mowing schedule.
The homeowner is responsible for making sure the grass gets watered.
Happy gardening in Hawaii. Gardens are where people grow.