Does he possibly have a mental illness such as bipolar?
Manic episodes can resemble drug intoxication in some people i've known over the years.
As Bearlove said, none of us can give you a definitive answer about what substances anyone may have taken - but to answer some of your questions;
- stimulants can certainly make people "wide eyed". This may or may not mean anything, but opiates don't generally do this.
I have never used crack, but cocaine in all its forms is a pretty short-lived stimulant. Unlike amphetamine, people can use crack/cocaine and go from being wired and super high to baseline - or sleepy - within a pretty short period of time.
- red eyes can be a result of many things - fatigue, sleep deprivation, allergies, irritating the eyes by rubbing them - to name just a few. Could he have been crying at some point just before this? Maybe a strange thing to ask, but some people's eyes look puffy and red for hours after crying, which can also account for emotional/erratic behaviour.
- falling asleep during meetings can be attributed to drug use (whether it is from sedation or exhaustion caused by not sleeping), but certainly not always.
There are obviously plenty of non-drug related causes for falling asleep at inappropriate times too - I've certainly been guilty of momentarily nodding off during extended periods of passively listening to someone talk - at office meetings, training sessions or the occcasional lecture back in my university days. None of these were caused by drugs - but probably had a lot more to do with lack of sleep.. Do you know if your partner suffers from insomnia, or had a late night?
I found that if i am actively engaged in a conversation, i am far less likely to find myself nodding off. Warm, poorly ventilated rooms can also make this worse.
Opiates can make your eyes red, but unless there is poly-drug use occurring, you would most likely notice a constriction of the pupils.
There is no way for us to say one way or another what the situation is - but i would urge encourage you to be careful about making assumptions without evidence - i have been accused of being on drugs when i'm completely sober, and it can be pretty upsetting. For some people, being accused of drug use could mean the difference between a 'lapse' and a full-blown 'relapse'. I dont mean to sound like that could put the blame on you - we all make our own choices - but being careful in how you approach your suspicions is important.
Having said that, i think most addicts of one sort or another can have a tendency to be dishonest - to themselves or other people; something i'm sure you're well aware of.
Communication is vital, but so is support and positive reinforcement - whether that is letting him know that you are concerned, there to talk if he wants to and/or encouraging him to seek other kinds of help if he is struggling.
I'm not quite sure from your post what the nature of your relationship is - is it an intimate relationship, or a business partnership or something along those lines? I think how you deal with your suspicions (especially if they are true) depends a lot on what the connection is between you. If the situation proves too much for you to cope with in your own recovery, you shouldnt feel obliged to help him; some situations can be worked through - whereas others may be harmful to get too involved with, if you arent already.
If there is a financial component (whether you are living or working together), i would be mindful of the potential for serious addiction to cost ridiculous amounts of money. Even if he is using occasionally, i would keep a close eye on any money or bank accounts you may both have access to.
Without wishing to stereotype, the drugs he has used in the past are extremely addictive, and even the occasional lapse into using is playing with fire - some people can manage to do so, but definitely not everyone. That is not to say that users of those drugs are bad people, just that they can get their hooks into people pretty deeply. Recovery can be a long, slow process - but that doesnt mean it is impossible either.
Wow - I didn't plan to write such a huge post - i hope it is of some use to you!
Oh, and welcome to Bluelight!