I have a special needs child. I don’t feel like I am getting anywhere. How do I know I am making progress? What is the meaning of success? I happened

Success is not having a credit card and success is not a product. A better word for success might be a process, or “growth.” Getting a credit card is often a milestone in a young adult's life. If the person has not learned to manage money, having a credit card can be a disaster. It was for me. I got into such debt that I had to have someone bail me out. I no longer even have a credit card even though I trust myself not to get in over my head again.
I had an experience that illustrates what success means to me. I was working with a two year old boy, a beautiful child. He didn't talk. He did what we call in Hebrew "hitkashkesh." That would translate as “scribbled," but in his case, it referred to his making noises instead of words. We teachers would speak to him as we might do with a six month old, teaching him to take turns speaking. We didn't use any baby talk with him.
One day, out of the blue, he began to speak in the most perfectly intelligible sentences. All the staff went bananas. We couldn't hear his voice enough that day or the next. It hit me that we had been having success with him every day, even though all we seemed to be celebrating on that one amazing day was a milestone he had reached in his development.
A milestone like that lets you know that you have been having successes all along. If we had been working futilely, he may not have reached that milestone so well or when he did.
Success is a process and life is a process. They are hopefully intertwined. They are like a ladder. You climb each rung, and reaching the top is a milestone, but you cannot reach it unless you are able to lift a foot and move your body upwards. Our children have successes every day that we do not always get to see. Maybe we think the day was unsuccessful because there was no visible achievement. But the milestone, even if we think of it as a product, is not the success. The child and his growth is the product, and as he learns to function like a typical child, he has to climb many rungs of a ladder, and he will not climb each rung in a day or even sometimes in a week or a month. But every rung that he climbs invisibly towards that milestone is a success.
Celebrate each day with your precious child. I did, and while it hurt to see her grow up so fast, moving from one stage into the next, I was thankful that she was growing well. In a pinch, my infant was a toddler and the day it hit me, I cried. In a snap, she grew up and is a woman. Now, I watch her in amazement as she resolves situations on her own as she makes shidduchim for others, enjoys and cares for her husband and raises her own child. I was successful. I hope someday you get to celebrate your child’s successful development.