needs some advice please

so my son is 4 and half yr old and his bio dad dont come around or call or nothing he only seen him 3 times out of his life i was texting him few weks ago askin if he wanted see aiden and he said yes and thats all i heard from him... he hast called or texted nothing at all should i let it go and move on or see if he still wants to come??? he never bought him anything or nothing i invited his family to his bday party they ddint even show up 🤦🏻‍♀️ i didnt think they would i asked all his family if they wanted be in his life and they dont care they dont ask me come rnd or nothing they blame it on me saying that is my fault blah blah blah... in my eyes they are all sorry as hell my son ahs autism and adhd sensory disorder.. but they nave everything to do with my sister kids and her because she married into the family... 🤦🏻‍♀️🧐