Are there grounds to contest this will?

My wife’s father remarried and both he and his new wife brought with them two children from a previous marriage. My wife’s father passed about six years ago and in his will it stated that his then wife would inherit everything unless she passed within 30 days in which case the estate would be split amongst the four children equally. I can only assume the 30 clause is there to avoid having to process two estates back to back but I’m guessing. However it does show his intent to have the four children share the estate when both parents had passed. This intention was stated again verbally by the step mother at the time the will was read and again years later. The step mother passed a month ago and we’ve only just learned after inquiring about the status of things that she willed everything to her children and left my wife and her sister with nothing. Are there any grounds to contest the will based on what her father’s intentions or are they completely at the mercy of her step mother?

Thanks in advance.

We have had a trustee in our family trust, a legal secretary, who has been dishonest and difficult, displaying bad conduct, where do I go to recover my funds?