1) there is no specific exit clauses (like notice period during or after probation, compensation in lieu of the shortfall, etc) mentioned in the appointment letter,
2) your friend's new employer do not want relieving letter
3) your friend can afford loss of a month's salary
4) your friend can take his new employer into confidence within short duration, in case of any background check;
ask him to leave and join new company.
I do not think filing a case by current employer will happen, even if so, that won''t benefit them.
From India, Pune
Anyone can sue anyone. However, the question is does such an action either benefit the company or will they succeed.
If I am correct, such actions usually do not succeed. It's a kind of bullying by the company.
From United Kingdom
This is provided for in most of the Shop & Establishment Acts
If the new company is willing to accept him without the relieving letter, then he is free to go ahead. The salary he has to forgo as there is no way he is getting that from the current employer.
However, it must be remembered, in future if he is joining a large company, they can ask for relieving letters of earlier employers and may also do background verification. That may be a problem. its best to leave after completing notice period.
The employer can sue, he has a right since its a breach of contract.
Its expensive to do so and a complete waste of time. However, if he does sue, your friend will find it very costly as he has to pay for lawyer fees and take holiday from office to attend the case for as long as it drags on.
(whether he will or not do it, depends on various factors which your friend will know better)
From India, Mumbai