That specific scenario does not line up with standard correctional practice, and we have never heard of a facility issuing a monetary fine for something like not making a bed.
Here is what facilities can and cannot do. The punishment for minor infractions like failing to follow housing rules, not making a bed, keeping a messy cell, not following a direct order, is disciplinary in nature, not financial. The typical consequence is a write-up that goes in the disciplinary record, a verbal warning, loss of privileges, or in more serious cases placement in the SHU. Fining an inmate money for a minor behavioral infraction is not a recognized disciplinary tool in any correctional system we are aware of.
What facilities can charge inmates for are specific services. Many county jails, including some in New York, charge a daily room and board fee that gets deducted from the inmate's account. Medical visits often come with a co-pay, typically a few dollars, that gets pulled from commissary funds. Some facilities charge for phone account setup or other administrative services. Those charges are documented in the facility's fee schedule and are applied consistently across the population.
A $25 fine specifically for not making a bed does not fit that framework. It is possible something was deducted from his account for a legitimate fee and the explanation got simplified or distorted in the retelling. It is also possible he is testing what kind of response it generates from you.
The most direct way to verify is to ask him to show you the documentation or receipt for the charge on his next visit or call. Legitimate facility charges come with paperwork.