Basically, the odds are against him not being a survivor.
Firstly, he is not on the medal roll for A or E Coys who were detached at Khelat-i-Gahizi at the time of the battle.
Secondly, he is not listed as being wounded, in hospital or duty in fort on 1 September 1880 (being the Battle of Kandahar).
Thirdly, almost all of the survivors of Maiwand were attached to Col.Daubeney's Field Force for the battle of Kandahr - only a few remained behind.
Fourthly, there were only a handful of men who remained behind at Kandahar under the command of Lt. Edwards who were on the sick list.
I have to admit that there is not known roll of survivors or of those who remained behind at Kandahar. However, I (and others) have done quite a bit of research into the question of making up a survivors list from the medal roll using information contained therein and from other sources.
I stand to be corrected of course. It could be said that the above is not substanial enough to place Cawte as a survivor. It must be remembered that almost all the regimental documentation was lost on the field of battle and never recovered. In addition other than the muster rolls after July 1880 and the medal roll, little else remains of any documentation in the confusion of the time. I would stick my neck out and say there is 90% chance of Cawte being a survivor - it is up to the individual to accept the odds. Of course his service papers (if they are available, and not all survivors papers are as I know) may throw up some more information on the matter.
If you are aware of something that I am not, then I would be most interested to hear - the jury is still out on much this particular field of research. I hope this helps and answers your question Hutch.