Resources to learn latvian

I'm brazillian and I want to learn latvian to talk to my grandpa in his mother language, but i'm having a hard time trying to find resources that can help me to learn it's grammar, pronunciation, etc. I could only find textbooks and videos that help me say things like "goodmorning", "thank you", "hello"...

I can speak both english and portuguese, so anything in those languages would be pretty helpful!