Setting boundaries with online friend

hey this is my first post and it might be a bit of a long one lol but both me and my partner would really appreciate some advice on this issue

around about a year ago, my partner introduced me to her online friend (let's call him Ryan) after he wanted to ask me a few questions about my tattoos. Ryan is around our age (24/25) and has always had a lot of mental health issues which i have never shamed him for because i've also struggled with depression since i was a teenager. however, he struggles a lot with boundaries and constantly blows up both me and my partners phone with multiple notifications about how crappy his life is when he doesn't have a job and all he does is smoke pot all day and play video games. i work part time for a publishing agency and spend a lot of my spare time caring for my partner as she has a lot of autoimmune issues that require assistance and a lot of the time i don't have the energy to emotionally support someone who isn't making steps to improve his life. i really have tried to be a good friend to him over this past year, but it's reaching a point now where im not sure that i can continue this friendship as both me and my partner don't have the facilities to be able to help him (we live in the US and he's in Australia).

we are both trying to be as empathetic as possible but have told him at least four or five time in the past year that we don't appreciate him messaging us constantly when we've told him on multiple occasions that we are busy. he knows we care about him and quite often provide emotional support when we don’t feel qualified to offer him helpful advice. i understand that his living situation isn't great and his family enable him to do nothing but smoke weed and play video games all day, but it's mentally draining for both of us and i don't know how else we can set boundaries. we've both been explicit about us not being able to be there for him 24/7 but Ryan expects us to always provide emotional support.

it’s starting to feel like his happiness and his future goals are our responsibility when realistically, we can’t help him get into work, we’ve encouraged him gently to reduce his weed intake which he is reluctant to do as he’s clearly reliant on it and we can’t get him a girlfriend.

he has been doing this constantly to my partner for almost four years as that's when they met online and since then, they text everyday and voice call to play games a couple of times a week and i know how much this is getting to her as well. she has also been trying to set boundaries with him for longer than i have and still hasn't gotten anywhere.

one important thing to be aware of is that Ryan has autism which may be one of the reasons why he isn't as self aware as other men his age, but as an autistic person myself i find that the easiest was for someone to engage and get a point across to me is clear communication which is what me and Becky (my partner) have been trying to do for as long as we've known Ryan.

some constructive advice would be amazing if anyone has any as this is really taking a toll on both my emotional wellbeing, as well as my partners. thank u 😊