As soon as the decision was made that my OH should not be sent to hospital for active treatment, an end-of-life care pack was delivered to the nursing home from the GP surgery - it contained sedation, pain relief, anti-nausea medication etc.
The nurses made decisions as to what he needed at any moment - and consulted me, as I was used to interpreting his needs - so he had a very peaceful death with his every need being dealt with promptly.
It was easier I guess because he was in a nursing home and there were qualified staff to make decisions about what was needed when; and able to administer it. I am so glad we did not let him go into hospital where it would have been busy with people calling out and rushed nurses. As it was, he was peacefully in his own lovely room with me by his side until very near the end (when I had gone to bed - the nursing home gave me a room so I could stay) - and all his family had been in and out throughout the process during the slow process.
During the two weeks he took to die, the nurses from the hospice were also on tap and visited regularly. His consultant came to be with us all one evening near the end and provided lots of information about what to expect, and reassurance that we had made the right decision to let him go in peace.
We were lucky - I cannot fault the care he received and the constant small acts of kindness to us his family.
I am sorry that your experience with your relative fell short of this. I guess this is because he was at home and there was no-one on tap to be responsive to his needs - and indeed your needs. I had spent many months trying to care for my OH at home, and I really do know how hard it is to be out on a limb trying to do your best but not having the skills, or, in my case, the strength. It may of course be that things were complicated by covid.
Reading your post makes me realise that we really were very lucky and that is a comfort to me - but I am so sorry that things did not go so well for your relative. 
On the subject of counselling services, I did seek some help after his death, as the weight of responsibility of having to make the decision to not treat was weighing heavily, even though everyone told us it was the right decision. I was lucky to find a good counsellor who has helped me enormously. I have a friend who is a counsellor and I asked her for a recommendation - word of mouth is the best source.