Any suggestions on how to limit my Dad's lottery spending?

I am in Massachusetts and my father is in Florida and alone. I have POA for him. He has multiple and serious health issues and I have just hired a geriatric care manager to take care of him and he also has senior helpers come to his home during the day. He also has early stage dementia/Alzheimer's (he has appt with neurologist this week). Obviously this is costly and he can afford it for now on his pension income. But he is depleting his bank account on lottery scratch tickets. He withdraws more every month than his pension provides. I am torn between thinking that he is a grown man and he worked hard for his money and he should be able to do what he wants with it. But on the other hand i don't think he realizes the gravity of the situation. I am also afraid that if I push too hard, he will revoke my POA. Does anyone have any thoughts or suggestions on how to deal with this? Thank you