Elderly alcoholic parent asking for food, wasting money. Are we responsible for a person who has never cared about us?

My husband's father is an alcoholic and is now elderly and lives on his own. My husband grew up in an abusive alcoholic home where the kids were not cared for and often went without food or clothing. His father was working but spent his paycheck at the bar for alcohol and gambling the same day he got it. As soon as my husband was old enough to leave, he did. We met, married and made it our mission to have a safe, non toxic home for our kids. We had been in touch with addiction professionals who encouraged us to set healthy boundaries with his family to keep our kids safe which meant not having a relationship with his family while they were in addiction, codependency and chaos. His mother died several years ago and there are two other siblings who are still living in the dysfunctional way they grew up.
My FIL would sponge money off his mother, my DH's grandmother, her entire life and when she died, he sponged money off his two sisters, my DH's aunts, and continues to do so. They all enabled him, gave him money, cars, a house, paid his utilities when he couldn't, all while he was still drinking heavily every day. The aunts have said many times they are glad my husband got out and changed his life from what he grew up in.
Fast forward about 30 years and my FIL is living in his home and his daughter is his primary care giver. She also has a history of not working much and sponging off the aunts.
A few weeks ago we were contacted by one of aunts, now in her 80's, explaining that my husband's sister was in the hospital and as a result, she was not able to get food to my FIL and would we mind getting him something. We reluctantly agreed, because he is elderly and we couldn't in good conscience let him go without food. We had not seen him in many years and he never contacts us. Neither does my DH's sister. DH took him food and saw that he was living in a dirty house with poor hygiene, as he always had. (that's how my DH grew up too) But we emailed the aunts to ask them if anyone has looked into plans for him and to explain his living conditions.
One aunt wrote back and addressed our questions and basically said that he is an adult that chooses to live like that, which we know. We just wanted to make them aware he was still the same. The aunt said that one of them was coming in spring to check on him. (they both live far away) She also said that his caregiver was discharged and able to go back to caring for him.
Then on Friday, we got a call from my FIL telling us he needs food. I asked him where his daughter was and he said she doesn't have any money because she's been off work. I asked him where his pension and social security is and he said he won't get SS until the middle of the month. I said we will get him some food and I asked if he mind if I contact some agencies to see if he can get aid. He said "go ahead, but I think I make too much money". He also told me that his daughter took him out earlier to "buy beer and cigarettes". My DH called her and told her that she is his caregiver and that he needs food. She got defensive with him and said she is not his caregiver. ?? She is on his bank account with him and pays his bills. She also takes him to doctor's appts, etc. She took him food and so did we. His father was under the impression that the aunts were paying us to bring him food, which we told him we were not. My DH's sister told him that.
I called aging adult services today and they basically told me he is an adult who is able to make his own decisions, spend his money the way he wants and has not been declared mentally incompetent. She went further to suggest that we start to try to have a relationship with him to make sure to remind him to eat or take him for groceries when he gets a check. !? We spent our whole lives trying to get away from the alcoholic enabling atmosphere and my FIL has had a lifetime of never having to do anything for himself; he has always had someone take care of him. We don't know what our legal obligations or protections are.
I called an addiction support to ask them how we are responsible if he chooses to spend his money on alcohol, cigarettes and gambling. She said alcoholism is the same whether a person is 20 or 70 and they don't have many elderly clients because of insurance. She suggested we contact a lawyer to see what we are responsible for. We feel like we are being forced to establish a relationship with him and take on responsibility that is not ours just because he is elderly and we don't want to be accused of being neglectful. Do we have to provide food for him after he spends his money on his addictions? Are we responsible for a person who has never cared about us? It's only now, that his sisters are older and can't provide much, that he contacted us. He also has several outstanding loans and debt. The aunts tried to help with bankruptcy but he bailed on that because he wants to be able to get more loans if he can.