My dad wants to use the same font as he used before in his previous work (he is nostalgic), but can't remember the name. Can anyone help an old man making "pretty email"?

If my memory is good, he used a Macintosh and it was around the 1990s.

 

What are we seeing there? Is that an old print-out? It looks like an old 1980s raster image, either coming from a dot-matrix printer or a bitmap font on the computer. Both are fixed-size font display systems. In either case, that’s not really how fonts work anymore. It’s really hard to emulate this kind of output with a scalable outline font.