Chinese herbal medicines are processed through suffering, and the pesticide problem you mentioned can be basically ignored after the high-temperature production process. Not all Chinese herbal medicines are polluted by chemical fertilizers. After all, Chinese herbal medicines are not food, so you don't have to worry. If you buy it in a regular pharmacy, the problem will be big. Don't worry.
reference data
Traditional Chinese medicine is mostly natural medicine with complex effective components, such as alkaloids, saponins, tannins, volatile oil and so on. Since it is a medicine, most of them will have different degrees of side effects. Generally speaking, the side effects of traditional Chinese medicine are less than those of synthetic western medicine, but some drugs are more toxic, such as red arsenolite, white arsenolite, mercury, Mylabris, green nymph, red nymph, raw gamboge and so on. Less toxic: Rhizoma Typhonii, Radix Aconiti Lateralis Preparata, Radix Aconiti Kusnezoffii, Rhizoma Pinelliae, Semen Strychni, Croton, Rhizoma Arisaematis, Radix Kansui, Rhododendron, Fairy, Venenum Bufonis, Eupolyphaga Seu Steleophaga, Luzongguo, Coriolus versicolor, Solanum lyratum, raw sulfur, Croton paste, Huang Dan, poppy shell, etc. Be careful when using these drugs, such as soaking flowers in wine. Oral administration can treat rheumatoid arthritis, and overdose often leads to poisoning death. Therefore, toxic Chinese herbal medicines must be taken under the guidance of a doctor.
I wish your grandmother a speedy recovery.