And where does he get the warrant for praying to Mary? Not from Scripture, where no believer prayed to anyone in Heaven but God. But if you declare yourself infallible, and then declare your interpretation of Scripture infallible - if it meets your infallibly defined definition of what is infallible - then Scriptural warrant is an option.
We do ask others on earth to pray, but Heaven is God’s domain, and correlations are limited btwn the two realms, unless you want to outlaw marriage altogether.
Catholics do not pray TO Mary; we ask her to intercede with the Father, Son and Holy Spirit on our behald.
And, yes, we pray directly to the Father, Son, and Holy Spirit too.
“Come Holy Spirit!” enlighten the hearts of your faithful.
The dogma of the intercession of the saints has little to do with papal infallibilty, and more to do with the longstanding teaching of the apostolic Churches -- Catholic and Orthodox.