I don't believe what they're saying about Dad's behavior, plus they don't give him the stuff I bring him. How do I get to the bottom of this?

My dad is in a facility w/ dementia. A woman of the many people there is telling me things about his behavior that I don't believe & I need to CHECK the facts? She's saying after my visit (only visitor person he has), he gets very hard to handle. She tries to tell me he "throws" his sodas I bring him all over the floor and makes a mess (he can hardly hold a cup). She says he uses the snacks I give him as weapons & all over the place (pastries, puddings, etc.). I have NEVER been allowed in his room (aside from COVID). Other visitors get to visit their family in THEIR rooms? The lady tries to keep me from visiting because of his "so-called" behavior, because she said then she has to deal with it. She just seems to over exaggerate EVERYTHING that might make ANY kind of physical/mental work on her or her staff. Also I have bought him at least 6 pairs of sweats (brand new all of these), four shirts, 14 pairs of socks, a nice jacket, a pair of slippers & he ONLY has 1× had on a pair of sweats I bought him. I do put his name on EVERYTHING. (I don't know whose clothes he is wearing.) Our outside visits he gets very cold VERY fast. Although everytime I ask to PLEASE dress him warm, bundle him up (I did buy gloves & a jacket & socks) because he will only last 10 min TOPS because he is too cold and wants to go back inside. They just REFUSE to do it. I HAVE been told (from an insider) that the place is not organized? Because for instance, there are quite a few employees there & "NOT EVERYONE GETS THE MEMOS!" I have seen & heard myself how unorganized & the "crap" that goes on there. I have NOWHERE else to put my dad.😥 BUT I think stuff is shifty & they won't let me in on ANYTHING. It's like pulling teeth. It is a Medi-Cal/ Medicare place. Shouldn't make a difference but sometimes the truth is... it does! Now I just CAN'T bring myself to "believe" "everything" this woman is telling me & I have to get to the "truth." I need PROOF. How do I go about doing that? In my past I've been too vulnerable & I won't let that happen w/ my father who doesn't deserve that. He recently lost everything he has worked for his whole life: his home, cars & ALL the surroundings, due to a wildfire. No insurance. That's sad in itself.😥 But then to think these people are taking advantage of him & not letting me visit because she doesn't want to deal w/ him. Come on. Oh yeah she also told me (laughing), "the kids, they ALWAYS want to believe their parents!" (Because of course my dad will deny doing these things) BUT I do know my dad better then they do. BUT I don't know ALL about dementia. I thought about putting a camera in his room IF they're not going to let me see what's going on behind closed doors.