welcome
do you know if he could manage sex before he got the anxiety? antidepressants are notorious for stopping ejactulation but the valium type meds cause no problems, but if off all antidepressants for a few months he should cope OK, anxiety seldom stops sex from happening
ativan and the other valium type meds will always stop or reduce anxiety or panic attacks if the dose is correctly adjusted, many of us carry a few tablets with us and disolve 1 under the tongue at the start of a panic attack, they work fastest that way ( sublingually)
antidepresssants work sometimes, must be tried for up to 6 weeks with dosage adjustment
self help books on overcoming agoraphobia or panic disorder have useful advice