Before you tell your son he has a drug addiction and you push him into something he might not believe he needs, take a moment to inform yourself of the situation as it is happening. Your post omitted a lot of information which makes responding to this difficult.
You said your son took pills of some sort and suffered from strokes due to that. But you also mention he has a drug addiction. How you do know he has an addiction to drugs? If your son had indeed taken drugs it could also be a sign that your son uses drugs for recreational reasons without being addicted to it. Many people I know in the range of 18 - 35 use drugs as a way that other people drink alcohol. Some people do it every weekend, others do it once every 2 months, but many of these people are not addicted. They don't need their drugs to be able to make it through the day. No, they use these drugs as they're intended: To create a different state of conscious for a more intense evening out. Everybody else use alcohol for that.
If your son hasn't openly admitted that he has addiction, please don't confront him by telling him, but by asking if he can explain it to you so you can understand. That way you don't run the risk of creating a negative / hostile atmosphere. If you let him explain his reasons it might not be as bad.
However, if your son does in fact have an addiction and he himself wants to break out of it then I strongly recommend you visit your physician. You are looking for specific medical information and the best way to get that is from a medical expert. He knows your situation, how strong your son's heart is and he can make a risk assessment based on know medical research. But realize that addiction is often a manifestation of an underlying problem, such a trauma. Going through an Ayahuasca ritual will not solve that problem. It might perhaps motivate your son to fix things up, but he will then also have to see psychologist or get some other kind of (mental) coaching.
I've seen situations where the parents confronted their children enraged and screaming in their faces without letting them express themselves. This led to a fight, damaging the bond between parent and child. Please avoid that at all times, because nothing good will come from that, for noone. Only tears.
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