My father-in-law was hospitalized for a heart attack. He doesn't have money to pay all the outstanding bills and did not reply to any bills. He wants to return to the US but without travel insurance. Because of the medical bills, this will he be prevented from re-entering the US?
Wow. Here I thought the US abolished debtors prisons in the 19th century. You can't get arrested for failing to pay a loan or a hospital bill or such (taxes and child support is an entirely different kind of beast). So if this is about a debt in the USA, you won't be held at the airport or anywhere else neither will you be deported. Law enforcement does not get involved in this at all until you have a court order to pay and you disobey that. In some states, you can be jailed in this case for contempt of court.