A relative of mine has agoraphobia – a fear of open or public places – and won’t go to church on Sunday for fear of a panic attack. Is this this person committing a sin by missing Mass on Sunday?
Illness is a legitimate reason to miss Mass, assuming that the person is doing what is reasonably possible to seek treatment for the illness. If your relative is claiming to fear a panic attack but is not seeking treatment through a physician and/or mental health professional, then there may be some culpability depending upon the person’s ability to seek the treatment. (An indigent person would have less responsibility to seek treatment for such an illness than someone who can afford treatment but refuses to seek it.) Your relative can obtain a referral to a Catholic or Catholic-friendly mental health professional through the Pastoral Solutions Institute or through CatholicTherapists.com.
By the way, while your relative is homebound from the illness, he or she can arrange with the local parish to have Communion brought to him or her at home by an extraordinary minister of holy Communion.