It is not a verb in that sentence. It is a past participle used as a modifier.
Student or Learner
"He is stronger compared to me".
"To compare" is obviously a verb but it doesn't sound like a verb in this sentence. Are there another verb with the same cases?
I would add that I would expect either:
He is stronger than I am.
He is strong compared to me.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.
Shouldn't the adjective be 'stronger' since you are making a comparison?He is strong compared to me.