Your friend can still go ahead with divorce proceedings even if her husband does not have legal representation or even if he ignores the process. There are many cases, especially now, where people are choosing to represent themselves even where the other party has legal representation. The proceedings will still be dealt with.
I think the problem your friend will face is that her husband will ignore the proceedings. Again this does not mean that your friend won't be able to get a divorce decree. After many applications to court for what's known as judgement in default your friend will at least get a divorce decree. The ancillary orders however, ie what happens with house, maintenance, pensions etc, will be more difficult to secure and enforce.
I would say if your friend initiates proceedings her husband won't ignore them for too long.