Looking crappy is not much information. There are a lot of settings in video editors that can make a video look crappy.
If it is choppy, he has to keep the 23 fps or once per second it will look like it is skipping, or even play at seemingly different speeds.
If people look all super slim, he has to keep image ratio the same. If it was shot in 1080p widescreen, he has to keep 16:9 format.
DVD can both have 4:3 or 16:9, so he has to look for 852x480. Usually, you DO NOT input custom resolution, as they are presets
you usually select. The scaling of the image gets mixed up sometimes.
Third, the compression algorithm, or codec. This is a pain in the butt. He has to select one that keeps file size decent while
maintaining a sufficiently good image quality. I am not familiar with Adobe Encore, as I use another software instead. If he
used a lower quality codec because of the time it asked for the compression, well, there is the problem. Even with a
multi-core CPU or GPU acceleration, converting a one or two hours video takes a good while.
With codecs you usually have to whether set bitrate or set quality. Setting quality is easy, as all you gotta do is set it to high,
and look if the software can fit it on a DVD. You usually have a bar going from green to red at the bottom of the screen when
you are about to burn it. If it's in the red zone, it just won't work. Then you lower the quality preset a bit. If using bitrates,
you have to calculate the maximum allowable bitrate . Keep an overhead for the TOC about 10% of the DVD.
If the video takes more than two hours, use a DVD-9 double layer instead, as it offers more space, so you can keep a higher quality.
Every modern house-common DVD Player is able to read DVD9 unless they are of the first batch.