Curliness of hair is an inherent quality of hair which cannot be modified.
Dryness and roughness can be improved with use of conditioner.
Oil usually does not help in improving texture of hair, and it may add to dandruff if you have.
Minoxidil lotion very commonly leady to dryness and flaky scalp, you can try foam preparation of minoxidil to reduce that.
Next Steps
Consult online for treatment.