Who can I trust?

From how your question reads to me, it seems he has gotten to stage 7 while these family members remain minimally involved. It seems like a lot to expect them to take on any serious care responsibility at this point.

If you have the opportunity to get him in the care of professionals, that is the route I would pursue. I have the same hesitation as you do about strangers. However I am often very impressed with how such people have been able to provide effective care for my DW. I have had some amazing experiences with the care strangers have provided my DW. Family members can often carry emotionally histories with PWD that can interfere with effective care giving, where as paid professionals do not.

When I originally contemplated placement, it was with the idea that DW would be placed once, until the end. I have since learned that is an ideal goal, but often not realistic. Do you best to get him somewhere so that you can get your life in order, but understand circumstances may change such that he may need to go somewhere else. Focus more on flexibility rather than perfection.

Considering your age and his stage of illness, placement would be the best for you both. Because of his younger age, he could still live for a considerable time. You are only 40, with dreams of your own, like having a child. Take a good hard look at what you are sacrificing by remaining his primary caregiver. Placement doesn’t mean you are giving up or that you don’t still love and care for him. It means the time has come where he can be cared for 24/7 by skilled people and it can provide you with time. Sometimes we feel we are doing what’s best for them because in our minds no one can care for them like us. The flip side of that is sometimes we aren’t willing to relinquish control, for whatever reason. Listen to the song by Glen Campbell, I’m not going to miss you that he wrote and sang to his wife as his dementia rapidly progressed. Heartbreaking but true.