This table is for four people, but when my father sleeps by the table, his legs get in the way and there is only room for three people to sit there.
通じますよ！ちょっと直させてもらうと、
This is a table for four, but my father gets in the way so only three people are able to sit here.
となります。
または下のようにも言えます。
This table is for four people, but when my father sleeps by the table, his legs get in the way and there is only room for three people to sit there.
「このテーブルは4人用だが、父がテーブルのそばで寝ると、父の足が邪魔で3人しか座れなくなる。」
「3人しか座れない」は
only three people are able to sit
only room for three people to sit
などと言えます。
ご参考になれば幸いです！
日本 
