"I noticed someone posted a GFM for their kitten's surgery and within a few hours already got over $2000 of donations"
2 options. The person had connections with "popular" people (at least locally) or, the one I see more likely, people helped just because cat. This may sound cruel, but people are a lot more likely to help a cute kitten than they are a self-described "autistic son". The latter is the kind of cause people claim to care at a respectable distance, not with actual care such as money donations. Animals, on the other hand, get everyone's compassion unconditionally.
…in fact, while kind of scummy, I would not put that possibility out of consideration if you are truly desperate: lie about the true cause for a more appealing-sounding one that could also fit the amount of money requested. Desperate times call for desperate measures.
OR, if all else fails, you can try pledging your cause to some numerous LGBT+ communties out there, assuming you have not done so already. If you can keep it a secret from your dad, this should help you get good traction from people who will sympathize with you much more easily. Mind you, I say LGBT communities, not just LGBT-friendly communities. The latter has the same issue of caring at a "respectable distance" as the rest, but I have seen the ones with actual LGBT people on them being much more caring of these things. They can maybe get the ball rolling for you here, you never know.
Do not give up just yet. If a literal potato salad can get thousands of dollars, so can you, and if I am wrong on that, then that will be on the top 5 list of most disappointing things humanity has shown me so far.