On an LLC. Can you write off a member removing investment as an expense? I thought it was classified as a loan.

No. In an LLC, you can't remove a member by writing off his investment as an expense. If the investment was a loan to the LLC, it's owed to the member and must be repaid. and not written off as an expense to lower your taxes.

does he owe the LLC the loan or is it the other way around?  if he owes the LLC money that won't be repaid then you may be able to treat this as a distribution to the member. These are certain reporting requirements for property distributions. in addition, if he is the only other member, terminating his interest terminates the partnership since there can't be a one -member/partner partnership, Consult a tax pro for how to proceed.