being unable to function for a week while sick?

this is regarding my boyfriend of 4 years, he isnt diagnosed at the moment but i am trying to see where to go from here and what doctors we should be seeking, living in a country with a bad healthcare system and getting tested for every possible thing isnt the most affordable or possible option at the moment, he is diagnosed with fibromyalgia and he used to have high blood pressure issues.

since we started dating he constantly disappear on me for periods of time whenever he feels not well rested or sick, he'd frequently be extremely tired but he'd chalk it up to work stress and fatigue, but i'd notice how even during his days off, he would be tired and constantly falling asleep while we're talking or calling, and during prolonged periods of vacation, the same pattern would happen, he sleeps through alarms, calls, people shaking him to wake up, yelling, he only wakes up once his body decides to. i'd like to also point out that he is almost guaranteed to fall asleep once he touches his bed even if he just woke up an hour or two ago.

usually when he'd get sick he would have to sleep through the day, he has to be on bed, cant text or call, and he hallucinates when he has fever. also his stomach has been a mess constantly lately, constantly nauseous, dizzy, sometimes his vision would be blurry, sore throat and constant fevers.

the first time he ghosted me for a prolonged period of time (more than the usual day or two) was in 2023 november, he got covid and it hit him pretty hard and it lased for 3 weeks, he was functional for the first two weeks until the 3rd week he completely ghosted me, stopped answering calls or texts and came back 4 or 6 days later saying how he was unable to function and barely got up to use the bathroom and drink water or soup then drifted back to sleep immediately.

second time it happened this severely was two months ago, it was kinda out of nowhere he gotten sick with what we think is covid again or the flu, he was supposedly 'fine' until he suddenly became unreachable and he stopped being reachable for a week until he got back in touch with me to tell me that day he said how he was fine he suddenly fainted after doing some chores around the house and then he got a fever and was sleeping the entire time and only waking up to use the toilet or drink water.

3rd time its happening right now, i cant reach him or call him for 7 days, family members say he is sick and unable to use his phone or do anything but lay in bed and sleep.

is this normal behavior for someone possibly with celiac?? or is this a sign of an something else? is it possible for someone to be sick with flu or cold to the point of being unable to do the most minimal tasks like holding the phone for one second.?