At what point do you start Pluvicto?

After the FDA just approved Pluvicto WITHOUT chemo, we're wondering if my husband would qualify for Pluvicto NOW? He's only done one dose of ADT and I THOUGHT it was plummet his PSA, he had the shot 2.5weeks ago on a Friday, then Monday had his bloodwork done and PSA went down a bit maybe 20-30 points, he had lowered it himself from 250 to 200 by taking supplements and diet etc....
He has stage 4 and it's in his lungs and bones already and still the only symptoms were peeing and ED..... after the ADT his symptoms are more tiredness and less strong (he goes to the gym daily)
It was a fight to get him to take the ADT shot to begin with and the other pills that are ADT and prednisone, he was told to not even start because his liver enzymes are elevated (because of his supplements)
Anyways, I know Pluvicto is ONLY used for castration resistant PC, but at this point, how do we even know? Part of what I'm reading online says he has to be on ADT for 18-24mths or something like that and the PSA starts rising again eventually, but another part says stage 4 that's metastatic like his is castration resistant, but that's only because the stories I've read the patients got diagnosed so much earlier and started treatment, I think my husband is unique in that it's such a devastating prognosis as the initial prognosis!!
Next week before Easter, he's going in for a chest CT and bone density scan, then the next day seeing the oncologist (and I think his second ADT shot- not lupron but firmagon) -a side note I remember from my other post there were questions about firmagon why not lupron but I think it's because lupron can make the testosterone/PSA shoot up and in my husband's case, you DON'T want that.
Also he's still peeing frequently, about every hour and a half at night, but last night was the first in many nights where he went 4 hrs! - don't think it's the ADT shot that's finally working, I think we just turned off the TV earlier than normal 🙂
My husband is going to get the blood test done again BEFORE the two appointments next week, so at least we can see his PSA and liver enzymes and at least him and I can THINK about stuff.
I feel so lonely and desperate, the doctors gave us/me hope of several years with treatment, but maybe it's just a money making scheme, my husband and I distrusts hospitals and doctors SO much, though I'm at my breaking point where I want to just give up and do what they say, my husband doesn't....so without treatment he probably has a year left!