Frederick is listed as dying of wounds to his head and shoulder on 1 Apr 1917 which were incurred on 28 Mar 1917 on the Maal Plain. A precis of the battle from C L Kingsford's The Story of the Royal Warwickshire can be found below.

 

Marching by night, at dawn on March 28 they arrived within 3000 yards of the Turkish position on the Maal plain. The 40th Brigade was to make a front attack, whilst the 39th was to turn the enemy's left. The attacking battalions in the latter were the 7th Gloucester and the Royal Warwickshire. The advance began at ten o'clock in terrific heat, with a mirage which prevented any definite view of the Turkish position. Nevertheless, though the ground was very flat with no cover, nearly a mile was gained. Then a halt was made till two o'clock, when the whole brigade advanced and captured the enemy's first line. It had been a sharp fight; in the Royal Warwickshire 3 officers were killed and 7 wounded, with 140 casualties in other ranks including Henry. Next day the Turks fell back to the Shatt-el-Adhaim and the Royal Warwickshire returned to Deltawa, where they bivouacked for a week. They then rejoined the brigade, and were ferried across the Tigris to guard the left flank. But the 13th Turkish Corps, which had been driven back by the Russians from the Persian frontier, was now approaching Deli Abbas. General Maude then recalled the 13th Division to take the Turks in flank at Shiala. A running fight ensued, which lasted four days, till the enemy were driven back into the hills.