Do they have this game in English? If they do have a patch ROM that can be read in English, I would love to play and learn this game to speedrun it

I don't know why I've never seen this forum thread until today!

There is no English patch as far as I've been able to find; this doesn't seem to be a particularly well-known game. I've looked briefly at it myself; I did find the text in the ROM and dumped it a while ago, but Game Boy games are so limited on space (both screen space and ROM space) that trying to actually fit a translation of any quality in would be a pretty intimidating project. Maybe I'll still take it up one of these days, if no one else gets to it first.

(A less challenging project would be a Lua script or something that overlays a translation over the game within an emulator, which wouldn't help much with running the game on real hardware but would at least be useful for enjoying the story casually or learning the menuing.)

If you're just interested in speedrunning and aren't worried about understanding the plot, it's probably a fairly approachable run to learn even if you don't know any Japanese. (I think @Megami_infini was able to do so just fine!) You really just need to recognize a small number of item names, plus learn how to recognize the correct answer in a couple of "riddle" sections.

My advice to anyone wanting to speedrun Japanese games would to be to spend a couple of weeks learning enough hiragana and katakana to at least sound out words in menus and recognize them by sound (especially since half of the item names in these games are English words anyway). In theory, that would be a small-ish time investment that would let you run pretty much any Japanese game you're ever interested in. But, plenty of speedrunners don't do so, and just learn visual cues for the particular words they care about in the game they're running.