Lady Regina wrote:
..I have a Canon Digital Rebel XT...
I'm going to recommend a different approach.
The Rebel XT is a fairly old model now.... introduced in 2005 and superseded by the XTi about a year later. Newer models have seen extensive improvement and added features.
I would suggest you give your XT to your husband to use and get yourself a newer Canon model. This way you can help him with advice based on your own experience with your XT, plus the two of you will be able to share accessories and lenses.
Assuming you want something fairly automated and easy to use, I'd recommend you look at the very compact, lightweight Canon SL2 or the Rebel T6i or T6s. The SL2 is a current model... the T6i/T6s are slightly fuller featured, but one generation older and can be found brand new on sale for about the same price.
One way to save money is to buy a refurbished camera from Canon directly. They sell them via the Canon USA website. There both the SL2 and T6i are currently on sale for $500, with an EF-S 18-55mm IS STM lens. There is also a T6i in kit with the EF-S 18-135mm IS STM lens ($650) or a two-lens kit including T6s, EF-S 18-135mm IS STM and EF-S 55-250mm IS STM ($750). All these are 24MP, 14 bit cameras (3X the resolution of an XT, as well as improved color gradation thanks to increase from 12 bit). Your camera can shoot continuously at 3 frames per second, while all three of these can do up to 5 fps.
All three of these cameras are also similar in other respects. They all have articulated 3", 1 million dot LCD screens on the rear (your XT's is fixed, 1.8" with just over 100K dots). They also all have Touch Screens (much like many phones) and built in WiFi (can communicate with a smart phone, etc.)
The SL2 uses a simpler autofocus system. It's 9-point with a single higher performance cross type point at the center (and fairly similar to your camera's). The T6i and T6s both use a more sophisticated 19-point AF system with all points the higher performance cross type.
The SL2 cannot optionally be fitted with a battery/vertical grip. Both the T6i and T6s can use the BG-E18, which doubles battery capacity and provides a secondary set of controls that are handy when shooting with the camera held in vertical orientation.
All three cameras use a newer type of battery than your camera. Among other things, the LP-E17 they use are not prone to "memory" effect problems, like the older BP-511 and similar sometimes have. I get a lot more shots per charge with my newer cameras, too. I used to carry two backup batteries for every one in my cameras, with the BP-511s. I now only carry a single backup. (This is a good thing, since the newer type batteries are more expensive!)
All three cameras also use SD memory cards, which are smaller and generally less expensive than the Compact Flash cards your XT uses.
Thanks to sensor and processor improvements, all three cameras also are able to make images at much higher ISO than your XT. Where your camera maxed out at ISO 1600 (and you might not want to use it due to image "noise"), these cameras have native ISO ranges as high as 25600, much of which is actually usable. That's four full stops higher and means being able to shoot in much lower light conditions than is possible with your camera.
Yet all three of these cameras also have a lot of automation to make shooting easy as you like... or more advanced controls if you want to use them. They will likely be pretty easy for you to learn to use, similar in many ways to what you use now... just "newer and better" in many ways. The T6s has more direct access to some of the most commonly used controls, compared to the other models.
All these cameras can use every EF and EF-S lens Canon has made the past 30 years or so. There are close to 90 of those lenses to choose among right now, in current production.
You mention wanting a telephoto lens for distant subjects and wildlife. Telephotos can get real big, heavy and expensive very quickly! I would recommend you try the affordable and reasonably sized EF-S 55-250mm IS STM (included in one of the kits mentioned above and linked below, though that kit is out of stock at the moment). DO NOT buy the cheaper EF
75-300mm "III". That is not nearly as good a lens (lacks image stabilization, has slower micro motor focus drive, and simply isn't all that sharp.... it's just the cheapest telephoto Canon makes). There's also a cheaper non-STM version of the 55-250mm.... it's okay but not as fast focusing. For more money than the 55-250mm, the EF
70-300mm "II" IS USM is an even better choice.
Canon refurbished camera site:
https://shop.usa.canon.com/shop/en/catalog/cameras/refurbished-eos-interchangeable-lens-cameras#facet:-810369798332821019810110832837650,-8103697983328210198101108328454115,-8103697983328210198101108328454105&productBeginIndex:0&orderBy:&pageView:grid&pageSize:&Canon refurbished lens website:
https://shop.usa.canon.com/shop/en/catalog/lenses-flashes/refurbished-lenses#facet:-8109841011081011121041111161113290111111109&productBeginIndex:0&orderBy:11&pageView:grid&pageSize:&Have fun shopping. Hope this helps!