Help with thoughts about fiancé possibly using drugs to cope with stress with ex


I’m not sure what to do.

My fiancé is going through a rough time right now with his ex. They’ve been separated for 13 years, had 4 kids and he’s still paying child support for the younger 2. Several years ago, she lied in court to get more money from him (lied and judge believed her which cost my fiancé a lot of money he didn’t have).
Recently, she’s trying to get even more money from him.
He’s having a hard time with the situation but does not let on how much it’s impacting him too much except for last night.
He was very down (crying a lot which is very unlike him) and through the course of the evening, as I was trying to be a supportive partner and listen and try my best to comfort him, I saw some signs that he may have taken something (a drug of some sort). He didn’t have much to drink yet his speech was slurred. Lots of other signs that he was off, in addition to beeing upset about the situation with his ex.

When I asked if he was “on something”, he got upset and defensive.
Long story short, I have empathy for what he’s going through and I’m worried about him.
I’m struggling with what to do or say to best support him. I want to coach him but of course I know that’s a bad idea.
So I know I need to coach myself.
I’ve done models but still not 100% sure how to think and behave through this situation.

U/M

C: M was crying last night
T: I want to “fix” it for him and make him feel better
F: sad and helpless
A: I try to find ways to control the situation
R: I can’t fix this.

I/M – what would love have me do? Who do I want to be in this situation?

C: M crying
T: I want to be the most supportive partner possible while knowing I can’t “fix it”
F: love
A: I listen and offer support in a non pushy, non judgmental way
R: I’m a supportive partner

Feels like I need even more thoughts to help me get to focus on love and support without trying to “fix” it because I can’t. I also have a big problem with him possibly using drugs. I don’t know how to approach this part in a way that will allow for him to open up and hopefully find better ways through the stressful time.