Help / advice for mother of 20 year old with ASD and LD

Hello everyone. I am new here and I really need some help. My 20 year old son is receiving  continuing health care (CHC) funding ( very challenging behaviour ) and has no social worker . He attends a day placement  (5 hours a day , 4 days a week on a 3:1 staff ratio). While I am very grateful to have secured  CHC funding and am able to work for a few hours a day , I am still caring for my son for the remainder of the hours he is not at the day placement and he does not sleep and is noisy at night. 2 bedroom terraced house - the neighbours have not stopped complaining about the noise at night . My some has been through a lot in the past few years including a brain bleed and has lost skills but is in a good place such that the challenging behaviours are minimal. While his support workers a lovely and care for him , the manager/owner of the day placement is unbelievable.- There is no proper supervision or training  of staff / risk assessments/ record keeping , staff are blamed for everything and staff turnover is high.  He is very good at talking his way out of situations , saying the right things to professionals and making promises which are never followed through. I have concerns  that started off as small things but are growing into more serious concerns e.g I spotted one of the support workers in the bank when she was supposed to be in the 3:1 staff support ratio .  CQC do not  investigate complaints About service providers . CHC seem to be annoyed with me  and making me feel like I am being difficult/ petty  .    My problem is my son is settled and happy and we have built a good relationship with his support providers ( because I treat them like human beings ) but I know that this day placement will not do anything more for him and if he is not stimulated enough may lead to challenging behaviours. CHC are reluctant about me switching to PAs . Is that the best it gets / is the system that broken ? I know that have said a lot and hope I have made sense. Any ideas/ advice/support  will be greatly appreciated . Thank you