Husband and I happily married 53 years, two adult children 44 and 42. One daughter 42 also happily married with family, we see them a fair bit and all good. AS 44 was a lovely child, no problem at all,academic and sporty. Went to university and started drinking, all downhill from then. After uni he got a job in finance, this had a drinking culture so it continued. He got married, his wife accepted the lifestyle until they had children, then she expected him, rightly, to grow up and curtail the drinking. He was coming home drunk pretty often or not coming home at all. This didn't happen. She divorced him after 10 years of marriage and he lives on his own. That was 6 years ago. Since then, he's deteriorated still working and drinking but mental health isn't good. He won't accept there's a problem, takes anti depressants but that's all. Access to his son is once a week on Saturdays which started off well, but now he lets him down regularly and doesn't turn up saying he's unwell at the last minute.We agreed with his ex wife that we would supervise on Saturdays as she was worried about her son and his dad being so mentally unwell. We also do it to give her a break from full time parenting as her parents are not really involved much. We get on extremely well with our ex dil, helping with childcare in the week, gardening, paying for clothes and hobbies for GS who is now 9. GS is delightful we love him to bits. There's been a pattern of our son seeing his child for say three weeks and then missing a couple. But just lately he's missing more and more. We're left with a very disappointed boy for the day. We still have a lovely time with him taking him bowling, swimming, cinema,to parks etc. We've tried having discussions with our AS but they go nowhere. It usually ends in an argument, he can be very sharp tongued, we feel very protective of our GS and try to get our AS to see what he's missing, but it falls on deaf ears.He just says we don't understand his mental health problems, but won't quit drinking and we think it would improve if he did.He does pay maintenance regularly though. Where do we go from here, any advice greatly appreciated. We feel like saying to our AS that we don't want a relationship with him, but then feel guilty. We are so disappointed and angry with him. We do love him but he tries our patience so much we don't know what to do. I think our ex dil also doesn't know what to do. She wants their son to have a relationship with his father, his child loves him and wants to see him, but being constantly let down is so hard for everyone.