my dad singing to him

My parents often come together to pick up  Mateo at our house but some mornings, my mom comes alone.
And the first thing Mateo will say when he does not see my dad around is  : Il est où Opa?

He loves to be with Opa.
When he is at my parents's, he spends a lot of time with Opa doing all sorts of cool things like : washing the car, looking for stuff in the shed, going to the park and on walks for hours, talking mechanics...
Singing is part of the fun too.  When we sing, Mateo always says : Encore !

Opa has always loved to sing.  He sang to me, he sang to my brother and he still sings to my mom.
I cannot say that he has a great voice but it is nice to see someone singing the same songs over and over again.
I have learned a few lyrics myself by listening to him.  "Your Spanish eyes, tear drops are falling from your Spanish eyes..."

 I wonder what song he sang for Mateo to smile like that and if he sang it opera style !  :)