Let Our Little Dogs Out With My Husband. Yorkie Came

Let our little dogs out with my husband. Yorkie came back in. Went looking for the other. Found him at the front porch on sife walk
Looked up at me. Call my daughter . Something us wrong. We picked him up brought him inside. He had bllod coming out his nose. Then it got worse. Starting coming out of his mouth really bad. We jumped in cat but he died before we got there. 3 years old. Why. What could of possibly happened