Will the couple be still in nikah contract if the man do not fulfill the condition put forward by bride before giving permission of conducting nikah?

Bride put conditions before giving permission to initiate the nikah that the Groom needs to pray salah 5 times a day all his life, if he promise for doing the same then I give my permission to do nikah with him. Initially, the Groom fulfilled the condition after the nikah moving forward by praying salah 5 times a day but later on he misses the salah oftenly and eventually ends up not praying the salah at all. So my question is that "Is their nikah contract is still valid or invalid since the conditions put before nikah by bride is not fulfilled?"