I agree with the ones who recommend setting firm limits. Gently but clearly if you can, if that doesn't work then more aggressively. But if he's a repeat offender as it sounds, you may want to consider dropping him.
I had something kind of similar happen earlier this year. On a local Asperger forum, I got a PM out of the blue from this woman. She seemed nice, so we got to keeping in touch by texts and the occasional phone call. But she got incredibly clingy, texting lots and lots every day, and our exchanges never got beyond the superficial and banal. We talked about meeting up IRL but it never quite came to be.
What really exhausted my patience was how I got shouted at angrily when I thought it was clearly undeserved. The first time was when we were on the phone and discussing meeting up. She had previously mentioned having chronic physical illnesses, so I thought I'd be considerate and ask "so you're OK with walking 1.3 km from the station?" This set her off something fierce, and while I eventually got the point across that I was just trying to be considerate, she never came close to apologising. The second time was when she texted, "Will you promise we'll always be friends? I've lost so many." I cautiously replied "we don't know each other that well, it might be a bit premature to make such a promise," and that set her off too.
After that I just kind of stopped replying to her texts, but eventually she texted me again asking "hey, what's up?" as if nothing had happened. I told her I didn't think things were going to work out, and the reasons why. After that we haven't been in touch.
In retrospect it does seem like she was looking for a bit more than friendship. I'd decided pretty early on I'd never be interested in her that way, but it never came up as an explicit subject, so it didn't occur to me she was looking for a relationship... but thinking about it afterwards, I think she'd made several attempts to come on to me (without even meeting me IRL). She'd also said things like "I'm having problems with my boyfriend" which taken together with the rest probably meant she was hoping I'd come riding in as a knight in shining armour.
I felt kind of bad dropping her since she seemed to be very lonely, but I don't think there was any other reasonable decision. While misunderstandings will easily happen with AS (after all, I have it myself, so I know quite well), getting chewed out for what I thought were quite transparently attempts to be considerate is not something I need, and we clearly weren't compatible in any way, shape or form.