Yes, a comic book series can be hiatus indefinitely. It might happen if the demand drops, or if the team behind it can't continue for financial or other significant reasons.
Sure it can. There could be various reasons like creative blocks, changes in the publishing industry, or personal issues for the creators that cause a comic series to go on an indefinite hiatus.
It's possible. Sometimes creators need a break or face unforeseen circumstances that lead to an indefinite hiatus.