A little late to the party, but it sounds like you got her typewriter into "line by line" mode, often shown as L/L on a button, maybe hit a mode or code button and hold it down.  These are usually toggle switches. Each time it is pressed, it reverses the current action.   At least that is how it works on my Brother Word Processors.  Yes, I have 3 of them.   I find them fascinating, especially when  they type every other line backwards, from right to left.

The only correction for the nylon ribbon would be to cover the image with white impression, then type over the  area.  I  hope I don't need any correcting abilities, because I will create all  documents in memory, then proof-read on the display, then print after making the  necessary corrections.

I am not aware of any interchangeability between different manufactures. If you have a Brother, you have to buy ribbons made just for Brother machines.  A Smith Corona ribbon will not fit a Brother machine  and  vice-versa.   Fortunately, most  Brother machines use the same ribbon, and the same print wheel, so they are interchangeable among Brother machines.

In a real emergency, you might be able take the  ribbon  out of a Brother cassette, and replace it with a ribbon  from a Smith-Corona,  but this is very tricky. It would probably be smarter to remove the old  ribbon leaving a short stub at each end, splice the new ribbon to the  stub, then wind  the new ribbon manually into the correct cassette, and splicing the other end.

I assume that among lesser known brands, there may be some interchangeability. Also, there are some 3rd party suppliers, who make ribbons to fit  Brother and Smith-Corona machines. I think  "DataPrint" is one, and  maybe "Nu-Kote."

The multistrike ribbon is 1031, and no longer available on www.brothermall.com   It shows "out-of-stock, discontinued."   So stock up if they fill your needs best.

I haven't tried my old 1030 ribbons,  but they have no expiration date or "best if used by" date on the package.  Since it is sort of a wax coating, they should be good unless exposed to high temperature.

I think the nylon ribbon will best suit my needs.  I intend to create documents in memory, and correct all mistakes before printing, so the correction feature is not necessary.  Long life is.  I don't care if it fades slightly before it has to be replaced.

Most typewriters that have a "correction" key, require the use of a carbon ribbon.  That is so the typewriter can backspace, and type the same letter, but using the sticky lift-off tape in place of the ribbon. If the machine is electronic, it will remember the letter, word, or line, to go back  and remove. On a non-electronic machine,  you will often have to manually backspace, and type the letter to be "lifted off" the paper, so you can replace with the correct letter.

The carbon ribbon is one time, it only goes through the machine once, then has to  be replaced. In fact, from an exhausted ribbon you can read what has been typed if you hold it up to a light.

The nylon ribbon is pulled from one side of the ribbon cassette and returns on the other side. It is continuous, so it can go through the machine many times, getting a little  lighter each time it goes through. The same as a manual typewriter.  They don't suddenly run out of ribbon, as can happen with a carbon ribbon.    That is my main reason for preferring a nylon ribbon. 

When a nylon ribbon gets too light, you can spray them lightly with WD-40 (light oil) and they will often come back to life.  Let it sit over night after spraying, to distribute the oil, and hopefully the ink too. You have to carefully remove the lid from the cassette to get at the ribbon inside. Be very careful not to disturb the ribbon once the cover is removed.

Brother at one time offered a "multi-strike" ribbon, which had about 5 layers of carbon on  one film. It would go through the  typewriter 5 times, before it was exhausted.  It is no longer offered.

I hope this helps.

I, too, have recently become  interested in electronic typewriters.  But I want a display so I can see what I have written before it is printed, so the bigger the display the better.  Two weeks ago I bought a Brother Word Processor from www.shopgoodwill.com for $3 plus shipping, and having lots of fun trying to figure it out.  Then it is interesting to see it print out my document, the daisy wheel going left to right, then right to left.  I have to resist the temptation to buy more daisy wheels with different fonts. I'd  love to find an inexpensive italic daisy wheel. 

Unfortunately, they are rather large, because the daisy wheel can't print in the first and last 2 inches  of  the platen, so 4 inches of width is lost.  But, being mostly plastic, and not a lot of real hardware, they are very light, so easy to  move and setup.