There's no way he can have legal right to it regardless of what he says and would be too expensive to try to sue over it just out of spite, other than that it just comes down to if someone thinks there is value in resurrecting it. Personally I have no intention of doing work on it or resurrecting it because it would take some time to bring it to POS only, not to mention that there is no financial benefit for me to take it over and simply do not have the time to develop on every struggling Coin.
Can you copy and paste other coins that utilize POS and reinserted into "new" LTCD coin? (I don't know, I have limited exposure when it comes to coding).....If you are interested, you could do premine (for development purposes), right?
It's X11 so you should be able to take an X11 POW/POS Coin and paste it over top and use the genesis Block along with it's nonce, merkleroot, pchmessagestart, checkpoints, and port numbers, then you set MODIFIER_INTERVAL_SWITCH as the beginning of Proof of Stake, LAST_POW_BLOCK as the end of Proof of Work and make sure you cut off the old clients prior to the start of Proof of Stake. You would need to make sure that all the Block retargeting is the same unless you want to change that as well in which case you would add in a fork for that too, basically you need all the Proof of Work and rewards to be exactly the same otherwise there would be conflicts.
This is an excerpt from bottlecaps where they rejected previous protocol versions, they just used bool bad version but you could set it as nTime in unix time as well.
https://github.com/bottlecaps-foundation/bottlecaps/commit/418ec73d2b800514fc1617633f1fe675e123cb88
It takes a bit of time but I would suggest for you to try to do it yourself, most everything you need to change will be in the src folder of the sourcecode.
I already took over PayCon and relaunching ColossusCoin 2.0 in the next couple days, I changed the algo for it to X13 for POW mining in the last few days but my test source was X11 and functioned very well as POS only so you could pull from that spot https://github.com/Crestington/Colossuscoin2test/tree/57aacedb2f9f3900e680bcdc16d52915988d799f
As I said, I cannot take it on because it's too much work to try to run more than 1-2 Coins but I can help you with advice on making some of the necessary changes. You'd also have to figure out what you want as your minimum and maximum Stake age and reward per year.
I'm have limited understanding when it comes to coding so I'm not viable candidate for the job.