Unless you have irrigation there is no benefit in trying to water with hoses or isolated sprinklers. Shallow rooted meadow grass could succomb but ryegrass will die back at the surface and recover as soon as the temperatures drop and moisture builds up again. Mowing should be as infrequent as posssible lifting the mowiing height just to maintain presentable cover. Aerating by spiking and vertidraining will only increase the water loss from a de-compacted surface. Any form of nutition without irrigation is of no avail – in fact nothing should be applied to the ailing grass cover at this time. Covers will help reduce evapo-transpiration and so will sand dressing – but if grass cover is wilting this should be avoided now.
Six weeks is a relatively short drought period and within a month we could wonder what all the panic was about. If meadow grass was dominant over-seeding with ryegrass may be worth considering.