1.Hello first look at the lawn and determine how much of it is weeds/ dirt versus dormant grass. next, find an agway or ag store near your house and ask them for a year long turf program. Pre emerge, weed killer with fert,winterizer for the basics.
If you have time maybe aerify, seed and starter fert the lawn before pre emerge needs to be put down. if not now definetly in the fall.
2. If you determine lawn is impossible to bring back, mybe you could get a landscaper to remove old stuff and sod. that way you would have something to work with in the future and you could fix any potential problems now.
3. If using the chemicals is a problem then for now at least put down some seed and ORGANIC fert. safe for everyone but a little more costly and get a landscaper for the pre emerge, grub control and weeds.
good luck hope this helps.