I would say, your EI people were totally wrong, and they should have told you that even if your son did not qualify for state services, that you should take him to get private speech therapy because the states qualification level does not mean that he did not need serivices at all. State services, like ECI and special education preschool, and then special education once he gets to elementary school are not designed to be all that any child needs. They are there to make them "functional" in the classroom. It would be my opinion, as an advocate for kids with special needs, that a child who qualified for a special education preschool a year after he was not qualified for an ECI program, that the ECI therapist made a huge mistake, or the agency had lowered thier qualifications to a dismal level, and that they did your son a huge disservice. I say it on this site over and over again...never wait on development, early is best, always supplement public with private service and get a private evaluation that you own, so that you know more about what your child needs than any public agency. What MR says is so true, and I see those kids she helps every day, and it is much more difficult to back track than it is to hit the issues head on.
Try to explain to your Mom that you hope she is right, but you are not taking any chances. Your brothter's experience, and any experience that any other single child has means nothing to your son. What matters is that he gets what he needs, and he gets it when it is most effective.
You need to know that the school district is doing what is appropriate for your son. Frankly, they almost never offer more than a child needs (they are not required to) and they very frequently offer much less than they need. I would not have a job it schools identifed and served kids well all the time. If I were to take a bet, I would be right most of the time if I guessed that your son needs more than the school distrcit is giving him. That is not to say that they are not doing a good job, that is just the conjuction of two realities. 1st, that the school really is not there to be 100% of any child's treatment program (if, that is you want to maximize your child'd potential-that is not the obligation of the school district) 2nd that many school districts don't even meet the standard of "functional" in a school setting.
That being said, make an appointment with a Developmental Pedicatricain. You can find them at children's hospitals, and you really need this kind of work up for your son. This kind of doctor will call in every specalist he needs and write up one report for you and tell you exactly what your son needs, and you will know that there are no state agencies or special edcuation directors who have decided to cut any budgets, no OT's with limited schedules, or missing intervention specialist from the staff that have influenced the recomendations. The things I just listed are not supposed to influence state run program recomendations, but they do, and the do so at a rate the keeps me busy. You need to know what you son needs, and you need to provide what ever the school does not in a timely manner so that your son does have that chance to be included (mainstreemed is not what you want, that word means that a child with needs is dumped into the regular education program without help or supervision-you want inclusion.)
It will take many months to get into see a Developmental Pediatrician. In the mean time, see a private speech therapis and OT and get evaluations, and start private thearpy in addition to his program. Make what ever sacrifice you need to. I would be willing to bet that you will be like almost everyone else, and that he will need private services in addition to his school serivices and that your private therapists will identify issues that the school district has failed to tell you about yet. The sooner you get therapy, the beter. The more therapy you get, the beter. Again, make the sacrifice, it is worth it in the long run, and the only thing you have that is free in the whole endevor is time, and you can't get it back once it is gone, and it is ticking away for your son.
What you are asking is, can my son be typcial later in life? Well, no body knows, but he has a better chance of doing that if you keep him in the public program and get him private serivices to supement his public program and know for sure exactly what your son needs by getting him a full private evaluation by a developmental pediatrician. I can tell you this, the real question you want to ask is, how do I make sure we get him the best services now, especially if he does not seem typcial once we get to Kindergarten? And that, is the same answer. You don't want to wait to up his services, you want to do so now. Hope for the best, but know that you have everything he needs if it does not turn out that way.
One last thing, you do not know what your son's diagnosis is, so while you can probably say that he does not have downs, you cannot say much more than that. He has not been seen by a Developmental Pediatrican and he needs to be to get a medical diagnosis. Go see one as soon as you can so that you know what you can say about your son. Schools do not make diagnosis...doctors do.
Good luck! log on to www.wrightslaw.com and start learning about advocacy too!
M.