Thrush, a fungal infection, is exacerbated by dry mouth, antibiotics. It feeds on sugar, yeast, alcohol and processed foods, so limiting those may help. Candida is normal, and needed throughout the body, but sometimes with a compromised immune system, illness, disease, it gets out of control, and the body is unable to keep the balance. It's easily treatable, but can get out of control otherwise. Sometimes the body develops a resistance to the medication, and needs to be swapped or need a higher dosage. I used 200mg or IV fungal medications, which I had too since it went systemic, including proper oral care, improving the immune system.

Good luck.