He doesn't have to claim to be Liectheinstain tax resident.
Under DTA article 10:
https://www.gesetze.li/konso/pdf/1970037000?version=3
1) Dividends paid by a company resident in a Contracting State to a resident of the other Contracting State may pay in the other be taxed by the state.
2) However, these dividends may also be paid in the Contracting State in which the the dividend-paying company is resident under the laws of this be taxed by the state; however, if the beneficial owner of︀ the dividends is a resident of the other Contracting State, the tax may not exceed:︁
a) 0 per cent of the gross amount of the dividends if the beneficial owner︂ is a company (but not a partnership) which at the time the dividends accrue, for︃ an uninterrupted period of at least 12 months holds at least 10 percent of the︄ capital of the company paying the dividends;
b)
15 per cent of the gross amount︅ of the dividends in all others cases.
But it's one hour drive to︇ Hungary or Slovakia and Austria has double tax treaties valid with both. Hungary CIT is︈ 9% (the lowest of EU) but you need to consult double tax treaties with both︉ countries.
Also all 3 countries are in Schengen meaning noboby will know if you really︊ went in the office or not.
Since you are a developer you could organize yourself︋ to go one day a week in your office.