Libel question

I am involved with my sister in a probate case dispute. She recently texted my nephew (her son) that I and my brother filed a report with DHSS (we did not) and told him my brother and I would lie about anything and everything. Is this considered libel?

Alasdair Taylor's answer to Libel question (879557657)

Answer to the question: 

This may well be a defamatory statement - in the sense of being a published a statement carrying a defamatory imputation - but I can foresee a number of issues if you decided to pursue the matter. For instance, you would need to show "serious harm" under s1(1) of the Defamation Act 2013 (http://www.legislation.gov.uk/ukpga/2013/26/section/1/enacted). I don't have any information here about the extent of the harm caused.