I can recommend accommodations like:
Booking the meeting space 10-15 minutes early and asking your member of staff to meet you early. Advise them this is to prepare for the meeting, or to write notes down to discuss X topic, or research Y. Ask them to get coffee or water for the table before the meeting if they’re junior. If needs be and you can afford the time, ask to see them 5 minutes before the meeting starts.
If setting a meeting, email in the morning when you check your calendar with a reminder of the meeting and its start time.
if you have a shared calendar like Google, set a reminder notice to the appointment of 15 minutes beforehand
setting a meeting right at the start of the day before person has the chance to get into 10 different tasks they are balancing, eg 9.30 or at the end of the day so they can wrap up work and attend the meeting.
dont forget the value of the FEAR in helping people be on time - so don’t be afraid to show disapproval of being made to wait or waste 30 minutes or if you have management responsibilities over them, to make it an area they need to work on.
BUT disabilities like these can really benefit from support, and alongside the shit you get with something like ADHD you get a lot of valuable positives and encouraging neurodiverse thinking in your workplace can be a big net gain. Problem solving, creativity, emergency support, multi project juggling etc - all big benefits to something like ADHD.
i will get a lot of snippy feedback to this post about how no one has time to make meetings accessible - but if you’d spend 5 minutes before a meeting sorting out the hearing system for a colleague who has a hearing aid, or always book the ground floor meeting for someone in a wheelchair, or if you print off slides as well as showing them on screen for a colleague with a visual impairement - there are some disabilities you are more welcome to support than others, and you need to think a little bit more about fairness.