It's fine apart from this: "Wouldn't it be tipping off then?" 'tip off' does not seem natural expression in this context. It is most commonly used when someone informs the police about somebody else's criminal activity, or you give someone some confidential information that you probably shouldn't be doing or or are not authorised to do. You could say: "wouldn't that be telling on her?" (i.e. giving the mother some private information about her) or: "wouldn't that be spilling the beans?" (Telling somebody about somebody else's secret plan)... Just some ideas...

"Wouldn't it be tipping off then?" > "tip off" is not correct in this context because we can only "tip off" the police, not a parent. However, there is no 'official' English verb to translate this meaning - there are many slang words, but each comes from a specific country and culture. The words I would use (I'm from southern England) would be "snitch" "rat on" "tell on" or "grass". I think "snitch" might be the most appropriate: "Wouldn't that be snitching?"

I mean besides not understand "Wouldn't it be tipping off then?", like who would we tip-off, Helen or her mother? Maybe it's just me being dumb, it's understandable to read for me, I wouldn't have any problems with it really

If you mean 'tipping off' in a criminal/money laundering sense I guess it is ok, because I suppose telling a family member is the same as telling the individual.