So, this is probably going to be a different one for most of you because the kiddo in question is 18, but they are in their senior year, so we aren't done doing the daily mom and dad bit.
Relevant background info: Kiddo's dad and I broke up when I found out my birth control failed because he wasn't ready to be a full-time parent, but I already had a 3 yr old and couldn't stomach the idea of terminating the pregnancy. We came to the agreement that I would raise the kid, he would pay child support, and unless something terrible happened to me, he wasn't expected to be involved. If he changed his mind later, he was in for the long haul. He's consistently been co-parenting with me since they were 9, and has always sucked with communication (would usually take several hours to a couple days to respond, but it has gotten to the point that he just doesn't respond at all most of the time, and I've been having to communicate through our kid), but definitely comes through when needed. Kiddo decided to go live with dad at 16 due to finding out they are highly allergic to cats. We have 3, and they didn't have the heart to make us rehome the cats because they had grown up with them. We had already tried everything from multiple allergy meds, shots and air purifiers, but to no avail. Dad doesn't have any pets, so this solution made sense.
Since the switchover, I have still been in charge of doctor's appointments, allergy shots, meds, school paperwork, all the admin stuff basically. Our kiddo is attending a school 30 minutes away by highway from where we live due to having ADHD and Autism, which our local schools were ill-prepared to manage. My fiancé has to be to work in the morning at the same time kiddo has to be at school, so kiddo's best friend's mom does morning drop-offs usually. Kiddo's dad was handling pickups last year, and I was stepping in as needed in emergency situations.
This school year has been a mess. BFF's mom and I are friends and tried to manage arranging transportation prior to school starting between the two of us because kiddo's dad wasn't responding to either of us. Admittedly, I have been getting increasingly frustrated with this because it's not like I constantly message him, or message about things that don't pertain to our kid. I wound up creating a group text chat with all of the relevant adults, me, him, his now-wife, BFF's mom, and my kiddo (added kiddo because they get anxiety about not knowing what's going on with transportation), because I only ever seem to get responses from him if it's been over a week, and we had a transportation issue due to schedule conflict on my end and BFF's mom's car was in the shop.
I explained that we needed to establish who was responsible for transportation on specific days as having to constantly change my scheduled appointments at the last minute was causing issues and stress, mainly money-wise because I was getting charged $75 every time I had to cancel or reschedule with less than 24 hour notice (I didn't share that part, or the following, but it's relevant to the problem). (But it was also causing a significant amount of stress because my fiancé and I only have 1 vehicle. And we can't save for a down-payment on a second one if I'm getting nailed all the time for missed appointments.) I shared my schedule for the next week and explained that I am trying to keep pick-up times free, but sometimes I don't have a choice, depending on what the appointment is for.
He did end up responding this time, but honestly, I haven't had any communication with him since the beginning of August before this, even though I have tried once a week to reach out, touch base and make sure things are covered for the kiddo. I'm at my wits end and don't know what else I am supposed to do. Yes, my kiddo is 18, but we are still legally responsible for them until they graduate, and as the parents, I don't feel like this is their responsibility to manage. Any advice?