My Boyfriend Recently Began Taking Welchol Due To Complications From

My boyfriend recently began taking welchol due to complications from having his gallbladder removed. He mentioned he wakes up with night sweats & now has insomnia, also, he has become very irritable? Is the irritability a side affect from this medicine? I'm concerned as he has never displayed such annoyed, almost, hateful feelings towards me and I'm uncertain how to comfort him?? Please help??