I think any direct relationship between the Indus Valley and the deep Dravidian south is unlikely because of the vast gap in space and time. Something like 2,000 years and 2,000 miles. But linguistically, if the Indus script is deciphered, we may hopefully find that the proto-Dravidian roots of the Harappa language and South Indian Dravidian languages are similar.
I don't know lots about history but I hope this helps you :)
The statement 'They allowed the Romans to focus more on expanding into the Western Mediterranean' describes the Punic Wars contribution to the development of the Roman Empire.
The Punic wars (264 – 146 B.C.) is a series of 'three wars' fought between Carthage and Rome, a then powerful city in northern Africa.
The war started due to a dispute raised in the Island of Sicily, which was controlled by Carthage. Carthage was an established naval power during the 'first Punic war' (264 – 241 B.C.).
But at the end of the first Punic war, Rome overpowered Carthage and became the land as well as naval power.
It also took control of the Island of Sicily. Meanwhile, Carthage was able to occupy power in the territories of Spain.
Carthaginian general named Hannibal invaded Rome during the 'second Punic war' (218 – 201 B.C.) with Spain as the base.
He emerged 'victorious' in the initial attacks against Rome. However, Rome under the 'leadership of a young general Publius Cornelius Scipio' chased away Hannibal’s army and from here seized the lands of Spain.
This allowed the 'Romans' to focus more on expanding into the 'Western Mediterranean'.