Is it permissible for an asthmatic to depart with the weak, and is he sinful if he misses the Fajr prayer due to a severe attack that exhausted him after taking medication?

A person suffering from severe asthma is considered among the weak, who are permitted to depart from Muzdalifah before others. This is the view of the majority of scholars. They are also permitted to return to Mina at night, and standing at Al-Mash'ar Al-Haram (definition) is waived for them. As for sleep that led to missing the prayer, if it was unintentional or due to forgetfulness, there is no sin in it. However, if it was intentional, knowing that the time would be missed, then one must repent and seek forgiveness.