I have only known this lady for about a year and we get on very well due to being the exact same age, having DC that are similar ages (mid/late teens) and similar senses of humour. Our interactions are mainly at work and we converse regularly via WhatsApp out side of work. She is divorced and lives on her own and her 2DC live 100% with her ExDH and visit her regularly. They are a 90min drive away. She holidays with them every summer but if she wants to see them or have them visit her, she has to drive there. My colleague and her ExDH appear to co parent very well: he invites her to Parent's Evenings for instance and They are very fluid with access to the DC. No animosity from what I've seen using the DC as pawns. For reference, the DC are privately educated and the ExDH pays for all school fees, school.holidays, etc
Before Lockdown started she admitted that she was an alcoholic and that she'd been a very heavy drinker. I'm now piecing two and two together and wondering if this is why the ExDH has majority custody of the DC.
We were messaging a few days ago as per usual, sharing photos of our DC, moaning about lockdown and then two days ago she rang me for a chat.
When I heard her on the phone, she sounded drunk but she said she wasn't
I wasn't convinced, trust me I've heard enough pissed people in my time. I spoke to her yesterday and she was very emotional so I asked if she had anyone with her (she didn't) and did she want some company. I went round to see her and she sounded exactly the same in person with eyes that slowly blinked. It didn't take too long for her to admit she'd relapsed 
I stayed for a bit and tried to comfort her but I don't have any experience of knowing anybody who is alcoholic so I'm unsure of the next steps. She does have family but they are geographically spread out around the UK and I'm aware she has some very good friends nearby but she is living alone to all intents and purposes.
My worry is when we go back to work, unless she gets to grips with this, she will be very likely drinking or drunk during office hours and I won't be able to help her.
She's been sober so she knows what to do but how do I get her to help herself? Can I do that?
By the sounds of what she was saying, her drinking was very hardcore years ago and she was pushing the limits which now makes me.realise if this was the factor in the divorce and why the children live with their dad.