Either the S8 or S9 will work. The two eventually go to separate places, (Mainz Hbf or Wiesbaden), but both go to FRA.
There is another option to the SkyLine. You can go by regional bus from in front of Terminal 1 to in front of Terminal 2. The bus takes 5 minutes.
When you come out of the Regionalbhf, which is actually under the building across the street from Terminal 1 but accessible via a passageway under the access road and stairs/escalators up into the terminal building, just inside the wall to the access road, take the first door outside, to the street.
Not every bus outside Terminal 1 will go to Terminal 2, but there are 7 or 8 per hour that will. There are four #61 buses, spaced about every 15 minutes that do. They come at approx. 5, 20, 35, and 50 minutes after the hour, plus or minus 1 minute. The bus might say it's going to "Terminal 2" or it might say it is going to "Südbahnhof". There are two #62 buses, but they come a minute before or after #61. And there are also one or two labeled "AIR", at 15 and sometimes at 45 minutes past the hour.
You can find the schedules on the Bahn website. Use from:" Flughafen Terminal 1, Frankfurt am Main" to: "Flughafen Terminal 2, Frankfurt am Main" and the day and time you intend to be there.
I rode it once, and it was very convenient because the bus was right there when I came out of the terminal. If you've come out from the Frankfurt Hbf to the Regional Bahnhof, your ticket should cover the bus as well.
If you do take the SkyLine back after picking up you husband, and you are using one of the free luggage carts scattered around the terminal, you cannot take it on the little train. You have to leave it outside the boarding area, but there will likely be another one at the other end, left there by someone going the opposite direction.