Thanks for the information.
I am sorry but I cannot give you particularly good news then. I’m afraid you are in difficulty here. There is one option though.
Obviously you are describing fairly horrible conditions. That is different from human rights breaches. You'll find quite a good book that here on that point
You could argue that being denied medical treatment amounts to a breach of the right to life.
You can obviously complain to the governor. You do have the option to judicially review the governors decision as an interested party. That is quite an expensive action but it is open to you.
I do understand the importance of key workers but that is not a human rights breach I'm afraid. The human rights act was concerned with really significant misconduct rather than departures from the ideal.
I'm afraid the absence of PPE is not a human rights breach either although if he were to contract the virus there may be a claim in negligence but that has not happened thankfully.
Everybody does accept that conditions in prison are much harder during the age of coronavirus and indeed there has been case law urging judges not to send people to prison or to reduce their sentences during this difficult time.
I'm sorry this isn't the answer you wanted but it is the position that you face and I have a duty to inform you truthfully.
Hope this helps. Please let me know if you need more information.