Parsing "他是…" in this short sentence

Question

I wonder if someone could help me correctly parse the following and explain why it should be parsed that way:

虽然我觉得他是想象不出来的就是了

Is the speaker saying:

Though, I think he can't imagine (that)/I think it's unimaginable for him

Or is it more accurate to say;

Though, I think I can't imagine him (like that/doing that etc)

Answer 1

This sentence is quite oral, 虽然我觉得他是想象不出来的就是了 == 虽然我觉得他想象不出来 That is:

Though, I think he can't imagine (it)

As for Though, I think it is unimaginable for him, you should say:

虽然我觉得这对他来说是不可想象的

And Though, I think I can't imagine him (like that/doing that etc) should be:

虽然我觉得我无法想象他（是那样的/做了那件事）

Answer 2

What did they say before this? Without knowing what came before, my guess is:

虽然
Despite the fact that
我觉得
I think
他是想象不出来的
he has no imagination
就是了。
it is just as you say.

Answer 3

Actually, if no more context provided, then this sentence could be interpreted in two different ways:

1. "他是想象不出来的"means that he is the person that you can not imagine [what he looks like, or what he would do, etc]. If the speaker are talking about someone that at least one of the speakers never met, then this part might have this meaning, and a clearer way to say is "虽然我觉得你想象不出来他[会做这种事|长什么样子]就是了".

2. "他是想象不出来的"==> "他想象不出来XXX", i.e., you think that he can not imagine certain objects or events. This might occur in the scenario that both speakers are familiar with this man "he". A better way to express is "虽然我觉得他想象不出来就是了".

Both of them are possible.