In the Lightning Network, what happens if a "middle node" suddenly goes dormant for a long while? I think I have a general understanding of how the Lightning Network works. However, I was having a little difficulty in understanding what happens when a node in the middle of a "path" suddenly goes dormant, or offline for a long time. To clarify my question, consider the following example:


A wants to make a payment of 1 BTC to D.
A finds a path from A --> B --> C --> D.
D generates an R and sends H = hash(R) to A
A creates HTLC of 1.002 BTC with B.
B creates HTLC of 1.001 BTC with C.
C creates HTLC of 1 BTC with D.
D unlocks HTLC, receives 1 BTC, and then tells R to C.


However, what if C is suddenly offline meaning C won't be there to receive R from D and thus stops the flow of R back through the path. I would assume that the HTLC's between A and B and B and C run out and so A and B are refunded. 

So, would C lose out? Would A have just made a "free" transaction? I assume this is a fast process, but is it likely such an event occurs where a middle node in an LN transaction just goes down for a long while?
If the transaction cannot resolve before the CLTV value of the HTLC runs out the peers will be refunded (the pending HTLCs cancelled) and the transaction will be cancelled.
If C is not there to receive R funds will not move so there is no need for force closures, but the funds will be stuck on the online channels as well for that period of time.
The online channels will be able to propagate payments in the meantime given there is more liquidity available and the number of pending HTLC-s is below the set limit.
See the situation where C would be online to receive R and go offline before propagating to B discussed in:
What happens if R is not revealed by one of Lightning Network nodes? (Payment cancelation)