My Q relapsed again and is now asking for money, how do I say no?

To preface- My sibling has gone to rehab twice this year for alcohol. They relapsed about 3 weeks after each stay in the facility. Now they quit their job because they were "asking too much of them", but they had nothing lined up to work after leaving.

Recently they have called me 3 times now, asking to talk because they're lonely but when we talked they seemed super giddy and all over the place, almost crazed and manic. They also only talk to me in the evening and will not answer my call during the day. I am pretty sure they're drinking again because of that behavior and the fact they told me they're isolating. Usually they like to call and talk about their emotions and make me their emotional punching bag, whether I like it or not, but this time was different. They asked for a large sum of money.

I don't want to give them money, especially since I know they will buy alcohol with it, but I am a people pleaser in recovery and I don't like making them mad because they are a monster to handle when they are upset. Actually, they are probably the reason why I am a people pleaser tbh. I just don't want to deal with it.

How do I say no?