Hi there, this sounds like a very difficult situation for you and I am sorry. I know of a great charity that supports people like yourselves nationwide. The family support programme is all remote and they help many families a year. Please see link and fill in the referral and someone will endeavour to respond within 24 hours.
https://www.adaptoxford.org.uk/support
They also provide free treatment to the substance user if they want the support themselves( under the adapt programme on their website)