No as I don't have one. I guess my options are put in some normal AAs and see if light works, swap original batteries for other AA rechargeables to eliminate batteries, buy a new charger
That more or less sums it up.
If the batteries were original, it's likely that they were standard NiMh rather than the low self discharge (LSD) variety, in which case it's certainly possible that the charge all leaked away and they've been sitting flat as a pancake for the last 6 months. Rechargeables generally don't like being run completely flat, and like being left in that state even less, so it isn't unlikely that one or more of the cells is dead. If you've still got the instructions, you'll probably find something in there about charging the light every 3 months or so if you aren't using it long term.
For new rechargeables, it would be best to get some of the LSD variety, which are normally sold as "ready to use" or "pre-charged". These will hold their charge for quite a long time, largely avoiding the "gone flat in storage" problem.
I use the black Eneloop Pros, but they are relatively expensive.
For a charger, there are any number of cheap "smart" chargers, but if you use rechargeable AAs or AAAs much, you would be better off with something like a BC-700 or a BL-700
https://www.batterylogic.co.uk/technoline-bl700n-battery-charger.aspThese will charge/discharge/recharge a battery, and report its actual capacity. This allows you to match up pairs and to keep an eye on the state of the battery, allowing you to avoid the other method of killing your AAs, which is to use a set where one goes flat whilst the others have enough life left to force current through the flat (and soon dead) cell.
With a basic charger, and using sets of 4, this may not be avoidable, as I've come across more than one new set where one cell didn't give much more than half it's nominal capacity until it had been charged and discharged on its own for 2 or 3 cycles.
In principle, it's better (for the batteries) to take them out and charge them in a decent charger, but there is a drawback to this - the wear and tear on the battery compartment catch.