Question for business owners.?

What I or anyone else might do is irrelevant. Your employer is under no obligation to offer you any "tokens" of appreciation. You should NOT expect anything more than a cost-of-living/inflation-based raise.  It isn't appropriate to ask for benefits that are afforded to full-time employees if you agreed to a part-time position without benefits.  You CAN ask. They CAN decline to give you anything. Then where are you?  If you aren't willing to quit, you have no leverage.

From their perspective you are getting a fair wage for the work you do and agreed to a job that gives you more than a day off per week and doesn't get paid vacation/personal time off, or insurance. Employers are more likely to "reward" an employee if the employee's skills are hard to come by.  If it would be easy to replace you, then it is unlikely an employer will go out of their way to offer you incentives.  It also depends on how well the company is doing overall. If they are making money hand over fist, the boss might feel more generous to all employees than if they are just scraping by.  

At a small company like yours, it would be most common to continue to get you raises on a smaller scale.  The company may supplement your income with a bonus during the year.

At large companies, to maintain equity, they would usually provide a once a year longevity bonus. 

If the company feels they can replace you with someone else for a lower wage, then there is no business reason to pay you more. At best, you could ask for a cost of living increase every couple years. Make yourself seen as the go to person and indispensable and you'd have a better chance of an increase.

As far as sick or holidays, if you're hourly part time that typically isn't offered.  Again, if they think very highly of you it's something they may offer.  It's a small office so they have flexibility to do what they want.  

I think this conversation needs to be with the boss.

I would give you raises. He’s probably limiting you to 30 hours per week to keep from paying for mandatory benefits. If I could afford said benefits, I would make you a full time employee.  That’s me, though. I have no idea what your employer thinks or can afford. 

Sorry but no. You have been given a job, these days employees should not expect perks just because they have been there for a long time.

Here in the U.K. all employees have paid holidays, maternity and sick pay. That is our laws. It seems very different in the US.

UK