Nothing seems to be working

I need help to try and find out how to get something to work. I have ADHD husband who wants to be around the family, help out with our child but never has time or energy to do it. I am going to take his word that he wants to do these things but its ADHD that is not allowing him to do it even though I have starting to second guess everything lately. I found the couples worksheet to work on, went on a 10 day vacation to work on it, decided before we went that the most important goal of the trip was to get that one thing done, reminded him almost everyday but the only time he could work on it was on the flight back because i was mad after 10 days of not getting it done. Since coming home, it is sitting on a table. I reminded him to create scaffolding to achieve it but it always has been some distraction or his "i will do it" which means it will never get done. I call him 3 times in the evening as a reminder for him to come home but none of those are taken seriously and he will not leave until i am either mad or dying. His parents are here for a month (cant say anything there because its the culture) and i have been asking him for a word that would make sure that i can break his attention in a way where it doesn't seem that I am an angry irritating bitch and their son's life is hell. They know about ADHD but do not believe in it and to them its my fault. Their son was a gem with no issues before he met me. Anyways, I don't have that word yet I am 100% committed to make it work and work with him but doesnt seem that there is any reciprocation. Yesterday, he was tired at 8:00 PM to talk to me but not tired enough because he came to bed at midnight. I tried to talk to him then, his reaction was that both of us are tired and not in the best mood to talk and we should talk in the morning. Spent 45 minutes to wake him up this morning but he wont. As everyone else, I do everything around the house from bills to everything about our child, the dog, and I cant get mad at anything he does even if it is scratching my dream car (which i waited for 15 years to buy) the week we buy it and ofcourse he is not going to do anything to fix it. He has the best intentions but no action. I want to help him and work with him but i dont know for how long can this go on as only one side pushing. Do you have anything that has worked for you?