The kiss of death is to say she has an American boyfriend. Absent that, she needs to be reasonably well off, with a very good job, own a house, own a business... Even then, they will probably be suspicious of a young lady visiting the USA alone.
Does she have Dual Citizenship? Lao/USA? Did she renounce her Lao's Citizenship? Can she get a Lao passport? If so, go home to Lao, get a Lao Passport. Enter Thailand with Lao Passport.
Pattaya wouldn't be my first choice for a long term stay, but it's great for a week or so. And good place to explore Thailand's Eastern Coastal Area. There are many options to consider near Pattaya. Na Jomtien, Hauy Yai, Ban Amphur, Bangsaray, Rayong, Sattahip... All of these are less than an hour from Pattaya, and less than 2 hours from Bangkok. Just 30 minutes outside of Pattaya, you can find peaceful places, ok beaches, nice local markets, local restaurants.... Yet, you're still close enough to Pattaya for the malls, shopping, medical facilities, movies, concerts, Muay Thai, gyms, restaurants, entertainment, trip to Koh Larn or Koh Samet, and yes the occasional night out.