So you have house power connected anyway, replacement batteries might be hard to find or expensive. Slowness can be attributed to a smaller processor and the memory at 512 megabytes. Here is a replacement battery. Google for the keyboard, I found one but in the UK for about US$150 - ouch! Google the RAM then Google again for a how-to on installing it.

You should be able to use a standard USB keyboard if Dad is not looking to travel with his find.

You can find out the CPU and installed RAM if you open windows explorer, right click My Computer and click Properties. It'll tell you the processor, speed and installed RAM.

It's relatively simple to replace a keyboard on a laptop. You'll want to shut off the power and disconnect from the power supply (and pull the battery even though you think it's dead). Then you'll probably need to lay the display flat. At that point, you should be able to pop out a flat piece that sits between the display and keyboard. The keyboard should then come out easily (there may be a couple of screws). There's a ribbon cable connecting it to the motherboard. Pull that out, put in the old one, put the flat thing back and you're ready to go.

But the USB keyboard will probably be cheaper and easier to install if you want to go that route.

yes, a usb keyboard works...will upgrading the RAM to 1GB make much of speed difference on the net...right now its like dial up speed.

What operating system are you using.
Does it look like a clean install or did someone just get rid of it with all the extra programs they installed still on it. If that is the case, there could also be too many programs loading at startup. Then Clear temp files etc do a defrag. Go to Crucial.com and put in the data for your laptop to find out what the max memory it will take. You will need a min of 1GB for things to run smoothly.
The latitude should have a number like E5500???

It running XP. There does not appear to be a lot of junk on it. I try your suggestions though...512 just does not sound like much memory. I know it has a 40G hd and 37G are free.