How can one achieve devoutness (khushu‘) in prayer and experience its sweetness, and is the prayer of one who prays in congregation with his family accepted due to the effects of medication?

Humility (Khushu') in prayer is a praiseworthy quality with immense reward. However, prayer without it is valid according to the majority of scholars, though it is deficient in reward. Therefore, prayer without humility is sufficient. A Muslim must strive to attain humility as much as possible. If it is difficult to achieve humility due to medications, then perhaps one will be rewarded the reward of those who are humble. As for the acceptance of prayer by Allah Almighty, that is an unseen matter, and it is sunnah (definition) for a Muslim to hope for the acceptance of their righteous deeds.