If he knew he had been exposed why infect your family, or was he just thinking he wouldn’t get it?? Sounds like he wasn’t thinking clearly.
He had a visa he’d received. He was exposed to ebola, in the vehicle with a very sick woman who died of the disease.
He had a ticket to the USA and exposure.
He likely came to the US because he wanted to see his family members here and be here for medical care when he got sick instead of in Liberia.