Struggling with a soon-to-be long-distance relationship

My boyfriend and I have been together for about 8 months. I am NT whereas he has autism. So far we have managed well in our relationship in terms of communication, however it is a different story when texting. In person we are both very invested with each other, he makes an effort to be invested in my life and tends to ask a lot of questions, I do the same. Our conversations are very much two-way. However, when we text it is completely different. He will not ask me questions about what I’ve been up to or how I am nor will he answer any of my questions in great detail. For example, I will ask him what he’s been up to and I will receive a one-word answer. I know he is doing this due to his autism and I have a lot of sympathy for that but I am starting to struggle with this communication over the phone. He will also rarely text me unless I reach out first which sometimes makes me feel a bit unwanted, he has told me he loves when I give him updates on my day and enjoys reading them because he misses me but that still doesn’t make me feel any better. Sometimes I think that if I were to never text him again he would not say or do anything about it. 

In September we will both be going off to uni, neither of us know which ones yet however there are two potential scenarios. One: he ends up at a uni 1 hour and a half away from me or two: we end up 8 hours away from each other. The first option would mean we could see each other during term time which would be ideal but the second option would mean not seeing each other in person for months on end. I am really worried that this will happen mostly because of his behaviour when texting, I’ve tried talking to him about this before and he understands where I’m coming from and says he will try his best to remember but personally I just can’t understand how he can think of me and it not occur to him to go ‘I should text her’ as personally that’s how my thought pattern is. But I know our brains work differently and therefore that is not how he thinks but I was wondering if anyone had any advice on strengthening our communication and/or helping me understand his thought process in this? I am desperate to make this work as I love him very much, despite this he is a brilliant guy and I am so lucky to have him but I am just really struggling here.