The solution to the whole matter depends upon your approach. You have to take care of the laws applicable for each scenario.
Example: Covering Under Social Security System
For example, if you really want to cover the person under the Social Security System (PF-ESI, Bonus, etc.), you can treat him as an employee.
However, as Mr. Harsh suggested, "how will you define and confirm that a person you employed as a part-time employee is really a part-time employee? If a person is working only for 2 days in a week, then he could also be working as a casual, temporary, or a badli employee/worker. Can you prove that the said employee is also working in some other unit/factory on other days of the week/month?"
So, you should first ask him whether he is not covered in PF-ESI in any other organization.
You can ask him to submit a request letter from his side to cover himself under PF-ESI. In your legal support, you can take a declaration from his side on judicial stamp paper. In the declaration he submits, the information provided by him is true. If at any stage the declaration is proved false, his employment and statutory coverage will be deemed to be withdrawn, etc.
Please note that coverage under PF-ESI can also lead to entitlement under the Bonus Act, Gratuity Act, ID Act, Employee Compensation Act, etc. (depending on your relations and circumstances).
Alternative: Professional Engagement
In the second case, if you don't want to subject him to any statutory compliances, please have a written agreement with him in which you appoint him as a Professional. In the agreement, you can decide the price of work, basis of calculation (number of days, job done, extra work, etc.), payment terms, and period of the contract.
The agreement should specifically state that he is engaged as a Professional and will never be deemed an employee of the company.
However, while releasing his payment, you have to deduct TDS (depending on the total volume in a Financial Year). He can claim a refund of the TDS after submitting his Income Tax Return if his total remuneration in a Financial Year is less than the taxable income.
I hope this meets your requirements. Fellow experienced members can correct me if any gaps are found.
Regards,
PAN SINGH DANGWAL