All he had left was Caligula (by then over 20) and Gemellus (under 10). Source: Internet
Some compare this to when Tiberius had chosen Caligula and the other grandson Tiberius Gemellus "without any approbation." Source: Internet
Caligula ordered Gemellus killed within his first year in power. Source: Internet
There would be more approbation for overlooking Caligula in Gemellus' favor. Source: Internet
Tiberius Claudius Caesar Germanicus II 'Gemellus', AD 19–23, died young ::B. Source: Internet
Tiberius had few descendants and Gemellus was the youngest of all of them. Source: Internet