Did you finish the novel?
Not yet. It's nearly complete, but it needs some huge edits and rewrites even if I didn't change the theme. The plot has holes, tiny holes, but enough to bother me. I know how to fix them, but it requires a lot of editing, and I see no point in writing the last 30 pages (even though I know how the story is going to end) until I've fixed the story so far. That way I can avoid creating any more need for rewrites.
Right now it's about 70k words, so it is kinda long and I definitely need to lower the word count. (The manuscript is in Finnish, and as the Finnish language consists of long words with no prepositions or articles, 70k is actually a very high word count even for a fantasy novel. Someone, somewhere, told me that to compare Finnish word count to word count in English it would need to be multiplied with 1,5, so in English it would be around 105k.)
Maybe wait and see what they say after they're done with the entire story? In the end, whether or not you choose to use someone's beta advice is always up to you; if you disagree, you definitely don't have to use it. But you could always test it on multiple beta readers and check the majority if you're worried about it?
I don't actually disagree with him. The family theme is great. I just started to think about this: as I sent him (in my opinion) the best the story can offer right now, and it was all about a family breaking apart, should it really be the main theme because even I, the writer herself, thought that it's the best part of the story?
But yeah, maybe I should give him a look at the entire novel (when I'm finished). It could be that he likes the real main theme even more. Well ofc it's not actually about only him liking the main theme, I have to be fond of it too, but here lies another problem: I'm not really sure what the main theme is, only that it's definitely not family issues right now.
So I have to figure out what is the main theme atm, do I like it, and is the family-issue-theme actually better. Lots of problems.
(And yeah, I did have an outline for the themes and plot and such, but then things happened and the story got out of control and the characters started to live their own lives and lost all respect on their creator, so all my beloved plans and outlines became useless )