My Husband Wakes Up Frequently At Night With Gas,mostly Esophegeal,

my husband wakes up frequently at night with gas,mostly esophegeal, which gets better when he gets out of bed. He has heartburn 5-10 times/mo and takes Zantac which helps. However over the last 2 wks or so cannot eat and keep anything down. I'm thinking he may have an ulcer...he has also been taking a probiotic for about 2 months and is also having diarrhea...any ideas?