There is a short chapter on him in the book, White on Green by Richard Heller and Peter Oborne which provides some background. They state he was the only Anglo-Indian to play for Pakistan. Anglo-Indian is a term to denote either those descended from British families which had settled in British India, or those descended from mixed-race relationships (usually between British soldiers, civil servants or merchants and Indian women). Heller and Oborne inform us that Sharpe "was born in Rawalpindi in 1937, into the third generation of a family that had migrated to British India in the mid-19th century."
Wallis Mathias is mentioned in post 4. He was another Christian who played for Pakistan but he was not an Anglo-Indian. As with Antao D’Souza (the third Christian to play for Pakistan) he was a Goan (some Goans had migrated from Goa to Karachi in the nineteenth century). The story of the other Christian to play for Pakistan - Yousuf Yohana - is of course well known.
Arguably the most influential Christian in Pakistan cricket, however was the administrator Alvin Robert Cornelius. Cornelius is better known for his tenure on the Supreme Court between 1951 and 1968, but as an influential figure on the cricket board in the early years, he did much to provide direction at a time of upheaval and in a context where resources were severely constrained.