Should we secretly stop paying grandmas electric and gas?

So I have a friend whom due a long illness she quit managing and asked dad to take over who inturn passed 6 rental units to Grandma. Within months they left Grandma in charge she stopped turning in all rent, began maxing out cards over 1k from tv jewelry. He had to decrease her business card to get her to stop. She still doesn't pay rent or utilities which the government gives her money for. His siblings raised by her live in two other units are the same way. He owner carried for one and she quit paying, burned it to the ground, then moved her 4 kids in with Grandma. She's manipulated the dad and he won't listen and now has turned him against the other manager who's actually turning in rent and doing his job! So Grandma keeps about 2k of the money a month and the dad is struggling trying to be a good son so why isn't she paying her 80 gas and electric. They want to "miss" the bill. Dad would throw a fit so it will be an "accident". What would u do? (I originally posted this on my facebook but because of who some of my "friends" are I couldn't say my friend is me. This is my stepdads mom. He's recently seperated from my mom so I think he's just trying to be connected to the only family he has but fyi she abandoned him as an infant and was one of those married then divorce to get citizenship then had 7 kids by different dads and lived off the government. You cannot expect someone who has no clue how to be successful to manage suddenly. She only knows how to get over. He fortunately completed college and became a very good moraled engineer. Very overly nice guy.)