[Need advice] Likely consequences of disclosing you have Asperger's Syndrome - given you have a 2.5 years gap in your resume?

You are right to be concerned that employers will be afraid to hire you because of your diagnosis, and an unfortunate consequence of the Americans with Disabilities Act (if you are an American) is that they will not be honest about this with you. The worst case from their viewpoint is that they hire you, find you don't fit in, but then are told they can't fire you because doing so would constitute discrimination. To combat this consider offering to first take a temporary part time or internship position so they can get to know you. My guess is that the first sentence of your post would greatly concern most potential employers.

I'm not sure about the timeline of your employment gap, but you might be able to use the fact that you have a special needs child as a justification for it.

There is a reasonable chance that your current employer assigns a high probability to your having autism because (a) of your behavior, (b) being told that your daughter has autism got them to think about autism and connect it with your behavior, and (c) someone realizes that your daughter having autism raises the probability that you have it.

Don't do it if you need money. It isn't that they are going to associate the gap in your resume with your condition (Currently Employed at Comparable Job is the gold star of resumes, nothing else matters nearly as much), its that they will DQ you immediately.

You work against this at your NGO, you know how real this is. If you google an applicant and you get mental health stuff its in the same category as "sued last boss" or "felony conviction". Dealbreaker.

Your profile states your location as Brazil. That means anything that somebody says that might be true for the US might not be true for Brazils job market.

In case you haven't already posted there, the Wrong Planet forum might give better help with this problem.

Since we're now about a year and a half on, how did this go?

If you think you will be let go from your current position in the near or mid future, start looking for a new job now. I'm not sure whether you will gain anything by disclosing your condition, vs. having the unexplained gap. Don't lie outright, of course. Can you say that you paused your studies to care for your child, without mentioning exactly what's going on? Your plans to return to grad school are a mark in your favor - that could also be a stated reason to switch jobs (i.e., "I want a job that will support me doing night school/ flexible hours for a year or two while I get even smarter").

Also, you have a Master's in EE. I'm guessing that's a field where there are far more jobs that qualified applicants, like basically all forms of engineering. That, plus the fact that even neurotypical engineers are really weird, and I wouldn't expect things to be too bad on a job hunt.