They will definitely pick it up so just be aware of this. Where and when is difficult to pin down with all of the repos taken place these days. Depending on the car value and all, it could be sooner then later. Actually you should remove tags and have them pick it up as you do not want any responsibility tied to the car. This gives you a clean spot to start. Do the right thing.
The vehicle belongs to the lender. You must cooperate with their efforts to pick up the car, but I don't believe you have an obligation to take it anywhere.
Depending on the value of the car, the lender may, or may not repossess. They may find it too cost prohibitive to reposses. For example, if the reposession cost is $1,500 and they are expected to net less than $1,500 after the car is sold at auction, they may just ignore it. Collections departments are not in the business of incurring more expenses. In this case, the car will forever have a lien on it. What happened when he called the bankruptcy department in December? If they won't reposses it, they may be open to an offer to purchase it from them. (E.g. $500 for a lien release).
I'd also be concerned about removing the license plates. In some states, such as California, the plates stay with the vehicle unless they're custom plates.
If I were in his position, I'd negotiate with the lender if I wanted to keep the car. If I didn't, I would keep driving the vehicle knowing that it could be reposessed at any time -- like while you're at the grocery store -- so don't keep anything of value in the car. If you use it, keep it insured. If you want to truly abandon it, research your state's procedures for releasing liability.
My opinion on the registration: The cost of paying the registration is likely similar to or less than the cost of an auto loan payment. If the lender isn't moving toward getting the vehicle, I'd renew the registration the last day before a penalty is assessed.