I'm troubled by this: either the person is financially competent, or they are not.
If he's genuinely not financially competent, then I would say the trustee should not be handing them $3000/month and trusting them to pay all their living-expense bills: gas, electric, auto insurance, car payments, etc. The trust should take those over and should own the car. Minimize the number of things the incompetent person needs cash for, to give them far less cash, to "sour the milk" for the soaking girlfriend.
Even grocery or eating-out money can be covered by supplying "gift cards" or retailer (trade) credit cards, e.g. they make Mobil credit cards only good at Mobil stations. He likes Applebees, give them a $100 Applebees gift card every month. If the girlfriend sells the Applebees cards on Craigslist to raise cash, then you have no trouble proving criminal elder abuse.
Now with that done -- to answer your question -- with that $3000/month chopped down to more like $700/month, now weekly or monthly automated transfers make more sense. Those are a lot easier to find, or simply do manually. Monthly or weekly is easy with PayPal, we use it for membership renewals.
It may also be a good choice for the trust to sell the house and use the proceeds to place him into a quality retirement village/community. Some of them are truly marvelous, and the sale proceeds and the $36,500/year will more than cover the expenses of living in a good one. Once he does, 90% of his daily living expenses are part of membership, and he only needs about $10/day for food to cook, offsite entertainment, etc. Maybe $20/day if he retains a car and needs to buy fuel and is going out more. That should "sour the milk" good-and-plenty for the soaker.
It also means he never has to mow a lawn again or fix a furnace or roof.
The retirement community also helps a lot if the state takes away his driver's license, either because he acted eccentric at a license renewal or got in an accident where senior-itis appeared to be a factor. My parents had to make that transition, and it was almost painless due to the retirement village they chose 11 years prior when they were active seniors. They get by fine on about $300/month.