A cursory reading of this article on Sky News definitely gives the wrong impression of the root cause.

The report begins with the statement "Air traffic control chaos that struck British airlines last summer was made worse by delays in verifying a password for an engineer working from home, an inquiry has found."

For a start, it is perfectly normal for a 2^nd line support engineer to be working from home. He was probably on call until the incident occurred, rather than working. This is done to save money and provide 24 hour a day support whilst allowing engineers some semblance of a normal life. Since this is a normal operating procedure, the systems that the support engineer needs obviously must allow remote access. The root cause of the problem was a design error with one such system: the "password login details 'could not be readily verified due to the architecture of the system'." In other words, the system was not fit for purpose."

The chaos was further exacerbated by the fact that support from the system supplier, Frequentis Comsoft, , was "not sought for more than four hours after the initial event". When it was, the problem was solved within 30 minutes. This is clearly an issue with the processes and procedures for problem resolution and escalation.

So no, the 2^nd line support engineer did not forget his password, nor how to connect via a VPN; the system was broken, as were the processes and procedures which the engineers were following. These conclusions can be drawn from the information in the article, but if one doesn't read it fully a false impression is given.