I've never had a problem with the basic functions of Font Doctor, including version 10.2.3. Though because I've been using Font Doctor for so long (my oldest receipt is dated February 2002) I rarely find a corrupted font anymore. FD did find some bitmap fonts in my /Library/Fonts folder that had no matching PostScript version. As it happens, I collected the fonts from AppleWorks 6 back in the day and there are Open Type versions of each of the bitmap fonts, so I replaced the bitmap versions with the otf versions and my installed fonts scanned clean.
I suspect that if Font Doctor is crashing on you there is something wrong with your system that needs fixing. That's often the case when software doesn't work. Some people's first reaction is to blame the software because that's easier than actually diagnosing the problem. Other times there are compatibility issues, though that's unlikely to be the case unless you're running OS X 10.6.8, Snow Leopard because this version of FontDoctor is compatible with systems back as far as OS X 10.7, Lion, which is rare these days.
In the past I have found corrupted fonts. Some could be fixed and some could not. That's the case with most things that get broken. When I couldn't fix a font I looked for a clean version in my extensive font collections. You can also find replacements online, but they usually cost money. If the corrupted fonts are among the fonts installed by OS X, then you may have to reinstall the system. It might be easier to install OS X on an external hard drive and replace the corrupted fonts (that cannot be fixed) with the clean versions in the OS X (macOS now) install. Of course you will need some basic knowledge about where OS X installs fonts before you can do this properly.
FontDoctor's weakest aspect is font organization. You would do better to use the font organization app built into OS X, Font Book—if you don't want to buy a major font utility like FontExplorer or Suitcase. OS X has it's own font organization scheme, which is another reason not to use FontDoctor to rearrange your fonts, unless you organize them within their installed locations so that the system and your applications can still find them.
Speaking of PostScript Fonts, I've converted most of my PostScript fonts to OpenType using FontXChange. This eliminates the need to keep track of the bitmap and PostScript versions. This isn't necessary, it's just a neatnick thing. ;-)