#1 And you don't know the answer to your own question? Do we or do we not know that the multitude was not literally Jesus' mother and brothers? There is an old maxim about interpreting the Bible "If the plain sense makes good sense it is nonsense to seek any other sense."And how is that different from Luke 8:21: "and he (Jesus) answering said to them (the multitude), `the mother of me and the brothers of me!"
Just because "he answered and said to him" doesn't mean he was addressing him as such. (Compare 1 Samuel 20:12: "And Jonathan saith unto David, `Jehovah, God of Israel -- when I search my father...")
#2 Context, context, context. This is a good example of heterodox yanking partial verses out-of-context desperately trying to support their false teaching. While the words were directed to David the context of the verse clearly shows Jonathan was praying to God. But context seems to be a foreign concept to you.
.....1 Samuel 20:12-13
.....12 And Jonathan said unto David: 'The LORD, the God of Israel - when I have sounded my father about this time
....to-morrow, or the third day, behold, if there be good toward David, shall I not then send unto thee, and disclose it unto
.....13 The LORD do so to Jonathan, and more also, should it please my father to do thee evil, if I disclose it not unto thee,
.....and send thee away, that thou mayest go in peace; and the LORD be with thee, as He hath been with my father.
And the we have the fact that we know beyond any question that David is NOT God. And unlike Jesus, in the 36 vss. I listed, David is not called or referred to as God any other time.