Traditional Chinese medicine (Zhong Yi) is much better than Western Medicine in treating 萎縮性胃炎. Zhong Yi can reverse腸化and cure 萎縮性胃炎. Western medicine can't. Western medicine uses anti-acid pills which may improve heart burn symptoms in short term but won't cure the disease.
I don't think your father-in-law should come to US for his 萎縮性胃炎. Ask him find a good Zhong Yi doctor in China.