My wife is disabled and she needs to renew her US passport. If I fill up the DS82 form, passport size of her photo and relevant fees, Can I come and get her passport without she coming to office?

You can do everything on line. Fill out DS82, Have a current photo 2x2, Pay the fee with check, include old Passport. If you want old one back, include a note saying so. If your not in a rush to get it back for a trip. You can do it yourself. If you are in a time crunch there are agencies that will handle that 2 weeks before your trip. Hope this helps.

That's a tough one. Depending on the disability I think it might work. Otherwise, I'd recommend you go in and ask.. but in general terms, you cannot receive passport on behalf of an adult or minor without their presence..