It depends what his goal with being sober is - if he wants to avoid all drugs then no it's not okay to offer him any, he's made a choice to stay away from all drugs and that should be respected, doesn't matter if the drugs are safe and most likely would be beneficial for him like psychedelics, if he's chosen to avoid that sort of thing then it's best you don't offer.
If it was just the problems caused by his addictions and such that he's wanting to avoid, and he isn't intent on keeping a "straight edge" type view on drugs and avoiding them entirely then I don't think there's anything wrong with someone who was addicted to a completely different class of drugs a psychedelic.
That said I also think it very much comes down to how you and him would use them. Although psychedelics are quite benign and largely beneficial in many cases there's a big difference between using them therapeutically and using them recreationally, and a lot of addicts need to get away from recreational drug use in general, so if he doesn't need them in any way therapeutically it might be something worth avoiding as it could trigger his desire to use other drugs recreationally and start up a vicious cycle.
Really depends on your friend, and I think you know him better than us.