Tom is an enigma,
intentionally!
Bombadil, to continue or even mere survival, requires a victory in the west, against the evil Sauron!
Goldberry, the river daughter, describes Tom as ‘He is’ implying that Tom is good?
https://dc.swosu.edu/cgi/viewcontent.cgi?article=2896&context=mythlore
https://en.wikipedia.org/wiki/The_Letters_of_J._R._R._Tolkien