Is there any internet service at the parent's house already?
If yes - parents can inquire about increasing service speed for the time period needed.
If no - For the limited time period in this case, it's not worth and probably not possible to get a hardwired solution. All major cell companies offer cellular based data packages at various speeds. Some options will require the purchase/rental of additional equipment. You should be able to browse these options and their cost on the websites for Claro, Altice & Viva before your wife arrives. Cellphone only data options will require a new sim card to be issued. This means that the phone needs to unlocked so that a different sim can be used and it helps if the phone supports the 3G/LTE frequencies used by the carrier you choose. Otherwise, you'll need to go with a separate "internet data box" option that provides wifi that the phone can then connect to.
Check with the parents to see if they have any knowledge of which company's cell signal is strongest at the house. If you opt to use extra equipment to connect to the carriers internet, change the default security options or your prepaid account credit will evaporate before your eyes as everyone within range discovers your new "free" access point.
Basically, figure out how fast you need the connection to be, in all likelihood you be using a cellular network option. Determine how much it will cost, go to the carrier of your choice with a passport/cedula, plunk down the money and you're good to go until you use up your prepaid data credit, then purchase more.