How long is a reasonable time to hold an item for someone ?

4 years ago my daughter was selling cameras for her elderly grandfather he had a large collection. She had a buyer that often held off shipping to see if there was more coming that he could combine shipping with. In the end, she moved away and stopped selling cameras - she messaged him to ask him if he was done (he has asked about more cameras) and that she wanted to send them. she never heard back from him at this point and she moved away. 

she has moved home some 4 years later and is back to helping her grandfather out again . two weeks later she has had an email from the bloke asking for his cameras and talking to reasons why he didnt reach out years ago such as had covid twice, and overseas holiday, sickness in the family etc, unfortunately a couple have already been resold (4 years later it never passed through her mind that some had already been sold and he never got back to her). where do we stand with this ? what is reasonable ? 

thanks in advance !