How to handle wife Isolating Dad w Alzheimer's?

Dad’s wife (both 91yo) has what we believe is stomach cancer. She’s been to MD Anderson hospital for a total of 4.5 weeks since end of Jan and is going thru immunotherapy. She keeps calling it a “blockage” so not sure. Dad has had cognitive issues for years. I always go to his medical appts w them so I know what’s going on. She has not attended his past 5 Dr appts due to health issues and she’s been in her pj’s since Jan. Dad diagnosed w late onset moderate-severe Alzheimer’s 2 weeks ago. I got a letter of (in) capacity but it’s being revised to include more details and fix spelling issues from their office. The social worker at their independent living( neither are independent but that’s another story) told us we REALLY need to know what’s going on because we need to make plans for dad (memory care) but she cannot disclose anything. Said wife would be out for at least 2 months at hospital. We later learned thru dad she is on hospice. I’ve been out of town and haven’t seen him in a week. Stopped by last night and his door was locked (never is). I knocked several times and dad kept saying come in, and will somebody get the door (he has full time home care and is barely mobile). I said I was going to call security if someone didn’t open the door. I called security and they said your dad said he doesn’t want to see you. That’s not like him as our entire family is very close. I see him several times a week and he always says to please call and he likes talking to us (kids). I asked dad (thru the door) if he had told security he didn’t want to see me. He replied “no” ( he didn’t say that to them). Security said they needed to go inside and talk to him. Security was there for quite some time. Security came out and said “they agreed no daughters were allowed in the apt. We can meet in the lobby or elsewhere though”. Dad doesn’t leave the apt at all. His wife had apparently arrived home sometime in past few days (from a hospice/ rehab center) and I found out from a neighbor she has a hospital bed. While I can understand her not wanting visitors, it’s isolating my dad. 90% of the time his phone is turned off (unsure who’s doing this) and now we can’t see him. If she really is on hospice, she could pass in a week or years. In the meantime, my dad w Alzheimer’s is losing cognitive function rapidly and may forget about his family by then. We also found out her daughter went to Fidelity where they have separate & joint accounts. There’s also concern the daughter is taking money from the joint accounts and dad will be left short of money for his on going care. She has MPOA for wife and I have it after the wife for my dad. So upset and confused now. My siblings and I are very distraught. Wife told security “no daughters” including her own. I don’t believe that she’s not allowing HER daughter to visit when she’s ill and can’t leave apt. I plan on calling our attorney on Monday to see options. Probably would cost tons of money to do anything. Security said “no daughters” so my brother is flying in from several states away in a week.
Any help/suggestions till I can talk to the attorney would be greatly appreciated. Sorry so long. So much drama has entered our family because of her.